Telecommunications Dictionary(C) Copyright 1991 R. Scott Perry Version 1.10 Last Update: 8/22/91 "What is this, why, and who is this guy?" I feel that this dictionary fills a major void. In my years of using BBS's, I have never seen such a dictionary. The closest thing I've seen was a text file that had about 40 words listed. These words included "RAM" "ROM" "Microcomputer" "Telex" and a bunch of other words that aren't really that important to under- stand telecommunications. I've seen some books about telecommu- nications in bookstores, but they tend to be expensive ($15-$49), and I don't recall seeing any dictionaries of telecommunications terms. Many terms are easy to confuse, and it can be very diffi- cult to find definitions for these terms. I have seen terms used incorrectly in advertisements by modem manufacturers and in major magazine articles. I hope that this dictionary can be used as a good source of reference for confusing terms. Why do I feel qualified to write a dictionary such as this? I bought my first modem almost 6 years ago, and have been using computers for twice as long. Not only have I used many different computers and modems, I have seen the days where 1200bps BBS's were rare, and most people had 300bps modems. And, for about a year I ran my own BBS, which was quite successful at the time. While I only had about 150K of storage for messages and files, I was able to get over 500 users in that year. I have also gath- ered, read, and searched through dozens of text files, program documentation, and magazines, just to help define words and find new words for this dictionary. I have also spoken to representa- tives of major companies to help find out the truth behind the terms. NOTES Note 1: It was difficult to decide what words to include, and what words not to include. I tried to include every term relat- ing to computer telecommunications that the average user needs to know, or might come across and be curious about. Some words are easily found in manuals for modems (such as PSK) but are hard to find definitions for. I tried to include as many of these as possible. Note 2: Since there are so many words defined here, and many of them are complex and easily misunderstood, I wouldn't be sur- prised if there are a couple errors of some sort. I tried to be as careful as I could, but it is possible that there may be some mistakes. If you notice any mistakes, or have suggestions of words to add (or take out), feel free to write to me. I'll correct any mistakes in future versions. MAKING COPIES OF THIS DICTIONARY Remember, this is not public domain, but it's not shareware either. It is copyrighted. All I'm saying is that you can't change it. I have spent countless hours searching through infor- mation, making phone calls, compiling the words, figuring out what some of the words REALLY mean, and defining the words. You MAY freely make copies (as a computer file, printed, or in any other manner) for anyone you know, just so long as you do not charge money for it. Any BBS may have this dictionary available for downloading, on the condition that users do not have to pay money in order to receive it. In the case of DISTRIBUTORS who sell public domain and shareware type programs for a nominal fee, I grant you permission to distribute this dictionary given 2 conditions: [1] You send me a notice of some sort notifying me that you are going to be distributing this dictionary, and [2] you do not modify the file in any way. Send the notice to the address given below. If you SELL any products (such as communications programs or modems), and wish to distribute this dictionary with your product(s), you MUST get my permission first. In most cases, if your product is legitimate, I would expect to grant permission. Send requests to the address listed below. If you wish to QUOTE this dictionary in any media, such as in an article for a computer magazine, you must get my permission first (the address is listed below). Again, I would expect to grant permission. Non-profit computer groups don't have to get my permission, as long as proper credit is listed. PAYMENT? If you felt this dictionary was very USEFUL, and you think that you would have paid money for it if it was in book form, I'd appreciate any donation. You are in no way obligated to do so, but if you found this dictionary very useful, and you can afford to part with a couple bucks, it would make me feel great. I'd recommend $5, but anything is fine. If you don't feel you can afford anything, but felt the dictionary was useful, a note of praise would make me feel good too. Any donations will be used towards setting up a support BBS for this telecommunications dictionary. "How do I reach the author?" Send any comments/suggestions/donations/notices/etc. to: R. Scott Perry 178 Morton Street Newton Centre, MA 02159 Hopefully, there will soon be a BBS to call to get the latest version of the Telecommunications Dictionary, as well as to use as an easy way to contact me. I hope you enjoy this dictionary! Notes about the entries ----- ----- --- ------- * [Also called more than one word for a certain concept. Do not bother looking at * [See also more information or an entry that may help you understand the original entry better. Also, a word and it's opposite will often refer to each another. * See the definition is the same as * BBS is used generically to denote any service that you can call up with your computer, whether it is a bulletin board, a pay service, or even a mainframe. * Note that many words have more than one definition--some that pertain to telecommunications and some that don't. Definitions that do not relate to telecommunications will not be listed. * Some entries refer to computers in general, but an understand- ing of them is sometimes needed to understand other entries. The Dictionary --- ---------- ---Numbers--- 8N1 - The most common modem set-up. [See also format]. 0004-0000-00345-4 - The stock number for "How to Identify and Resolve Radio-TV Interference Problems," as listed in almost all manuals for hardware. If you want a copy, write to: US Govern- ment Printing Office, Washington, DC 20402. 103 - Officially, `Bell 103' which is the standard controlling transmission at 300 bps in the United States. It was created by AT&T. [See also 212A]. 202 - The mode used by the Applecat modem and CATFUR. 212A - Officially, `Bell 212A' which is the standard controlling transmission at 1200 bps in the United States. It was created by AT&T. [See also 103, V.22]. 300 bps (baud) - A transmission speed that is quickly becoming outdated (though most modems will allow communication at the speed) that is roughly equal to 30 characters per second. 1200 bps (baud) - In the mid 1980's this was the most common transmission speed, until 2400 bps became popular/cheaper. It is roughly equal to 120 characters per second. 2400 bps (baud) - A fairly high-speed transmission speed that towards the end of the 1980's gained popularity. It is roughly equal to 240 characters per second. 3400 hertz - The highest pitch that a telephone line will trans- mit. This cutoff limits the ways in which computers can communi- cate over telephone lines. 8250 UART - The UART on most computers. [See also UART]. 9600 bps (baud) - At this time, the fastest transmission speed available for commercial modems. 16450 UART - The UART on some 286 computers. [See also UART]. 16550AFN UART - This is the UART on some newer computers. It in- cludes buffering, so that if data comes in faster than the com- puter can accept it, the UART will hold the data (up to 16 bytes) until the computer is ready for it. [See also UART]. ---A--- abort - [1] The command word used with editors that allows you to exit, destroying your message. [2] The character used to stop characters from a block of text appearing on your screen. Usual- ly the spacebar or CTRL-X are used to abort a message. access - [1] (verb) This is when someone is using a BBS with their computer. "My boss was accessing a BBS bulletin board when he was interrupted by the doorbell." [2] (noun) Refers to an intangible amount (usually represented by a security level or flags) that indicate to what extent you are allowed to use a BBS. When used in a term such as `you will be granted access', it means the amount of access that new users will generally receive. account - A term that refers to information that a BBS has about you. It is usually referred to by an ID number or your name. The information it contains can include any information that you have at some point given the BBS, usually including your name and phone number. [See also ID number]. account number - See ID number. Acculink - A packet switched network that is used to save money on long-distance telecommunications. ACK - A character (CTRL-F) that acknowledges something, usually that a certain amount of data has been received correctly. [See also NAK]. acoustic coupler - A cradle in which you would place the handset of a phone. This would be connected to a modem, and the modem would access the phone line through this coupler. Modern modems connect directly to the phone line. acoustic modem - A modem that uses an acoustic coupler. [See also acoustic coupler]. adaptive data compression - See ADC. adaptive dialing - When a modem can determine whether to dial pulse or tone. It tries dialing with tones first. If that doesn't work, it will dial pulse. ADC - Adaptive Data Compression. A method of data compression developed by Hayes, with a possible compression ratio of 2:1. alias - A name that users can use on a bulletin board that is not their own. Aliases are usually used by young BBS users and those who pirate software or do other illegal activities. Some exam- ples of aliases are `Cracker Kid', `Starbuck', and `Midnight Killer'. [Also called handle]. ampersand - A character (&) that usually means `and'. analog - As far as electronic signals are concerned, analog refers to signals that can represent an infinite range of num- bers, as opposed to digital which can only be distinct whole numbers. Analog data often comes from measurements. The sound a modem makes over the phone is analog since it can be any number of different frequencies. [See also digital]. anonymous - Refers to an author of a message that is unknown. On some BBS's you are allowed to post anonymous messages so that others won't know who you are. The SysOp usually can find out who the author is, however. ANSI - ANSI is a set of cursor control codes which originated on the VT100 smart terminal. Many BBS's use these codes to help improve the sending of characters to communications programs. It uses the escape character followed by other characters, which allows movement of the cursor on the screen, a change of color, and more. answerback - When a communications program sends information in response to a ENQ character. answering computer - This is usually the BBS or mainframe. In any case, it is the computer that being called. [See also origi- nating computer]. answer frequency - The frequency that a modem uses when it has been called by another computer. [See also originate frequency]. answer mode - The condition in which a modem is ready to answer the phone when it rings and prepare to connect with another modem. All BBS's are in answer mode. [See also originate mode]. apostrophe - The character '. It is usually used in contractions of words, such as "don't". append - To add to. Some BBS's allow you to add text from anoth- er message to the message you are posting. ARC - When a filename has the extension ARC, it means that it is an archive compressed with the program PKARC. To get the files out of the archive, you need to use the program PKXARC. You should be able to find this program on many BBS's. [See also archive, unarchive]. archive - [noun] A group of programs that are together, usually compressed, in one file. [verb] the process of combining those files. There are a number of software packages which will com- press files into an archive, and most BBS's have programs that are archived with one of these software packages. [See also unarchive, compress, ZIP, ARC, PAK, LZH]. area code - The 3-digit number used by the telephone company to designate a geographic area. Each state in the United States has 1 or more area codes. If you call a phone number in a different area code, you must use the area code before the phone number. If you call a number within your area code, you just dial the phone number (if it is long distance within your area code, you must dial "1" and then the number). ASCII - An acronym for American Standard Code of Information Interchange. It uses 7 bits to represent all uppercase and lowercase characters, as well as numbers and many characters and punctuation marks. ASCII often uses 8 bits in the form of bytes and ignores the first bit. [See also EBCDIC]. ASCII transfer - When a text file is sent directly as it is, without any special codes. asterisk - The character *. asynchronous communication - This is when the beginning and end of each byte that is sent over the phone lines is marked somehow. This way, if there is line noise, the modem can find out right away where the next byte should start. [See also synchronous communication]. AT command set - See Hayes AT command set. at sign - The character @. Often read as 'at'. AT&T - American Telegraph and Telephone, the inventors of the first modem. attended mode - This is the mode that a communications program is in while you are operating it. [See also unattended mode]. audio monitor - A speaker that is part of the modem and allows you to listen to whatever sound is on the phone line. This is often used to hear busy signals or make sure that the other modem picks up the carrier. auto-answer - When a modem has the ability to automatically pick up the phone when the phone rings and attempt to connect with another computer. auto-baud detect - The ability of a modem to change to a lower bps rate if the computer it is calling is unable to communicate at the requested speed. auto-dial - When a modem is capable of dialing a phone number, so that you don't have to dial manually. auto-download - The feature of some file transfer protocols where a BBS can automatically cause a communications program to start a download or upload. This saves some time for the user, who would otherwise have to set up his program to upload or download. auto fall-back - See fall-back. auto-kill - A feature on some BBS's that will delete a message on a board if a certain threshold limit is reached. For example, a BBS might delete the second message on a board if there are already 100 messages and someone posts another message. auto-redial - A feature that allows a modem or a term program to dial a number again after it finds out that the number is busy. This is very handy when trying to get through to popular bulletin boards that are often busy. auto-reply - To send a message (either public or private) immedi- ately after reading a message on a BBS. Usually, this is used to respond to the author of the message. auto-save - The ability of a terminal program to save information that it receives from BBS on disk that it was originally storing in memory. This way, if there is more information than will fit in the buffer, it will not be lost. auto-syncing driver - This is part of a BBS program that automat- ically determines the bps rate of a caller. [See also manual- syncing driver]. auto-typing - This is when a communications program can upload information to a BBS as if the user were typing in the informa- tion. For example, the user might have a message typed into a file, and then the communications program can send it to a BBS that assumes the user is typing the message directly. automatic adaptive equalization - This is when a modem has the ability to adjust to lower speeds if necessary. ---B--- backdoor - A way of getting into a BBS and getting full access, without using a regular account. Usually the author of the BBS program built the backdoor into the program so that he could get access to any BBS running his software. backslash - The character \. backspace - The character (CTRL-H) that causes the cursor on your screen to move back one space. [See also destructive backspace, non-destructive backspace]. bandwidth - A range of radio, audio, or other frequencies. Telephone lines have a bandwidth of 300 Hertz to 3400 Hertz. Since it is so limited, it a modem must careful change data into sounds that "fit" within this range. Similar to frequency spec- trum. bannerware - A software program that is free to use and copy, but somehow advertises another program or product. baud - A term referring to the speed at which computers communi- cate. Officially, it is the number of changes in an electronic signal per second. Since the number of changes usually is the same as the number of bits sent or received per second, bps and baud are often used interchangeably. However, there is a differ- ence, which is very often confused. Many 1200bps modems are advertised as 1200 baud, even though they operate at 600 baud. They send out 2 bits 600 times a second, which means that it is 600 baud. However, since it is so often misunderstood, you can assume that when you see "baud" it means bits per second, unless it is stated otherwise. The term comes from the scientist J. M. E. Baudot. [See also bps, dibit]. BBS - An acronym for Bulletin Board System. Usually it is a home computer that has a modem attached and is waiting for calls from your computer. It can, however, also refer to commercial serv- ices (such as CompuServe and the Source) and any other computers that you can call via telephone lines. BBS's almost always allow you to leave messages for other users. Many BBS's have programs that you can download and use on your computer. BBS can also be expanded simply to `bulletin board'. Bell 103 - See 103. Bell 212A - See 212A. bisync - Refers to a modem that synchronizes with an electronic signal over the telephone lines that marks the beginning of words. Don't worry if you don't understand this term. bit - A Binary digIT. It is a number in base 2, which means that it can only be a 0 or a 1. It is used in the expression `bits per second'. [See also byte, word]. bitstream - BBS's and related activities. For example, you could say that a lot of public domain programs can be found in the bitstream. blind dial - This is when a modem will dial a number without waiting for a dial tone. Some long-distance telephone services will require a number to be dialed, even though there will be no dial tone. In this case, your modem should be set to blind dial. block - A group of characters. For example, when downloading a program, blocks of 128 or 1024 characters are often sent. board - [1] See BBS. [2] A group of messages on a BBS that are related. For example, a BBS might have a board for general messages and another board for messages dealing with computers. [Same as subboard, message base]. bps - Bits Per Second. The transmission speed of most modems is measured in baud or bps. Bps is literally the number of bits sent by the modem every second. [See also baud]. braces - The characters { and }. [See also left brace, right brace]. break character - This is a signal sent from one modem to another that lasts for about a second. It is sometimes used to try to clear up synchronization problems. browse - To go through the list of titles of messages and note which ones you want to read. buffer - [1] (verb) To save all incoming data in memory. [2] (verb) to temporarily save data until the computer has a chance to use it (using interrupts). [3] (noun) The place in memory where the saved information is stored, as in "I have a 32K buff- er." bulk mailing - Used on a BBS when you send the same message to more than one person. This saves you from rewriting the message. bulletin - A special message posted on a BBS, usually written by the SysOp. In most cases all users are expected to read any new bulletins that may have been posted since their last call. bulletin board - [1] See BBS. [2] See board (definition #2). bulletin board system - See BBS. busy - When a bulletin board is being used by a user, or when the telephone line is being used. busy signal - The sound that you hear on a phone when the phone number you are trying to reach is being used. It usually con- sists of 60 cycles per second. [See audio monitor]. byte - A group of 8 bits. It usually represents one character. [See ASCII]. ---C--- call back unit - A device that, after you connect with a BBS and tell it who you are, will then call your phone number. This is used to make a very secure system to prevent hackers from invad- ing a system. It then becomes very difficult, if not impossible, for a hacker to get into the computer system. caller - Anyone who connects with a BBS. It is usually used in a phrase such as "You are caller #4328." caller log - A list of callers who have called a BBS within a given time period. The list may also keep information such as the baud rate of the caller. This is used so that the SysOp can keep track of users, as well as the occasional hacker. call progress monitoring - This is when your modem tells you what's happening when you dial another computer. It will tell you that it has dialed the number, if the number is busy, if you connect, etc. call waiting - A service that the phone company offers most customers that allows the customer to hear a special sound on the phone if there is an incoming call while the customer is talking with someone else. The customer can then talk with either call- er. This is a nice service unless you have a modem and call BBS's. If you are connected with a BBS and someone else calls you, you will be disconnected. In most areas there is a special 2 or 3 digit number that you can dial before a phone call that will temporarily disconnect call waiting. capital letters - See uppercase. capture - To 'catch' text that is being sent to your computer from a BBS and put it in a buffer or a file. capture buffer - The area in a computer's memory where a terminal program stores incoming data that is to be saved. [Also called capture memory]. [See also buffer]. capture memory - See capture buffer. card (peripheral) - Any computer peripheral that can be connected directly, without any cables, to a computer. Internal modems are usually peripheral cards. caret - The character ^. carriage return - See return. carrier - The tone that the modem sends over the phone lines before any data is sent on it. It has a fixed frequency and a fixed amplitude. carrier detect - The wire in an RS-232C cable that holds the information as to whether the modem senses a carrier. [Also called CD]. carrier detect threshold - A way of measuring how well a modem can detect valid data over noisy phone lines. It is measured in negative dBm's (decibel-milliwatts). The bigger the number (the more negative) the better. For example, -45 dBm is better than -40 dBm. [Same as receive sensitivity]. carrier frequency - This is the frequency which a modem uses to transmit or receive data. CB simulator - A computer service where there are multiple phone lines (usually at least 5). The CB simulator allows all the users to send messages to one another while they are on-line. It usually allows both public messages that everyone who is on can see and private messages that only one user can see. CCITT - Comitte' Consultatif International Telephonique et Tele- graphique. This group, created by the United Nations, estab- lished certain standards for data transmission. The transmis- sion, data compression, and error control standards all begin with V, for example V.22. CD - See carrier detect. center - Some editors on BBS's allow you to center a line of text so that it appears in the middle of the screen. character - Any letter, numeral, or symbol. characters per second - The number of bytes or characters that can be sent over the phone lines in 1 second. This is determined by dividing the bps rate by the number of bits it takes to send one byte (usually 10--the start bit, 8 bits of data, and the stop bit). So, a 2400bps modem can send 240 characters per second (2400/10). [Same as CPS]. chat - A mode that allows two or more people (almost always a SysOp and a user on a BBS) to communicate with each other using the modem. Usually, each person can see what the other is typing at all times and can interrupt them (a beeping sound with a CTRL-G is useful to interrupt with). chat mode - This is when a communications program is set specifi- cally to chat with someone else. One way this can work is that anything that is typed by the other computer is printed on the top half of the screen, but anything you type would appear on the bottom half of the screen. [See also chat]. checksum - A number that represents a larger group of numbers in order to check for errors in data transmission. It is commonly used when downloading a program. The checksum is the result of a mathematical equation, such as adding all the numbers in a group together. chip set - A group of important IC chips on a modem (or other computer peripheral) that are all made by the same manufacturer. While there are many companies that make modems, there are only a few that make the chips for them. Because the chip manufacturer is making the chips for many companies, they produce more chips, and the price of the chips is lower. This decreases the price of the modems on the market. Christensen protocol - See Xmodem. circular dialing queue - This is used in some communications programs to allow you to enter a list of phone numbers to call, and it will keep going through the list and dialing numbers until it reaches one of them. This is useful if you are trying to reach BBS's that are busy. city code - With some foreign countries, you need to dial a city code before the phone number you are trying to reach. You must dial the country code before the city code. clear to send - See CTS. columns - The width of your screen as measured by the number of characters your screen can fit across it. BBS's often ask for your screen width. Most current computers have a screen width of 80 columns. command buffer - The place in your modem's memory where it stores the commands that you give it. [See also buffer]. command set - A list of all the possible commands that you can give something, such as a modem, a BASIC program, or a BBS. commands - Instructions that you can give to a modem, a BBS, or another similar device. commercial host system - An on-line system that you can call up, that is operated by a company that charges to use it. commercial software - Software that is copyrighted and may not legally be distributed by BBS's or copied and given to other users. communication - The idea of transferring one's thoughts or ideas to another person. communications program - A program similar to a terminal program but somewhat better. Often used interchangeably with terminal program. compatible - When one object can work as another. Though the term is usually used with computers, it is often used with mo- dems. Many lesser known modems are compatible with more popular modems. compress - To make data take up less space. Archiving programs do this, which means that files will take less time to transfer with modems. [See also archive]. compression ratio - The ratio of the original size of data that is sent to the compressed size. For example, a 3:1 compression ratio means that the original data takes up 3 times the amount of space as the compressed data, and a modem would transfer the data 3 times as quickly. computer network - See LAN. configure - To set something to your liking. To configure a BBS, you may have to tell it your screen width, whether you need line feeds and other such information. configuration - All of the information that you used to configure something. Configuration is often used to describe what equip- ment you have for your computer (your computer configuration). connect - [1] To be at a point where you can start communicating with a BBS, as in "I have connected with the BBS." [2] Any point after you have established contact with a BBS, as in "I am still connected with the BBS" or "I have been connected with the bulle- tin board for just over an hour." connect speed - The speed, in BPS, which your modem uses when it connects with a BBS. This speed will depend on the speed of your modem, and the BBS's modem. It will be no higher than the lower of the two speeds. If you have a 2400BPS modem, and call a 1200BPS BBS, your connect speed should be 1200BPS. connection - The actual contact with a BBS. It is used most often in expressions such as "I have a bad connection," meaning that there is line noise. continue - To pick up where you left off, usually after pausing in the middle of a message. CTRL-Q and the spacebar are used most commonly to let the BBS know that you want to continue. control character - Any of 32 ASCII characters that do not print on your screen or printer. These characters are usually used to control your computer. [See also CTRL]. copyright - A term meaning that a program or text file is pro- tected by the government so that it may not legally be copied, except to make backup copies. You should not upload a copyright- ed program to a BBS, unless it is shareware or freeware. [See shareware, freeware]. Co-SysOp - A term similar to a vice president. The Co-SysOp of a BBS has more access to the BBS than any other user except the SysOp. The Co-SysOp might check messages to make sure that they are suitable for the BBS (not containing illegal messages), and he may be able to validate users. Sometimes a Co-SysOp is just a title given to someone who helped the BBS a lot by doing things such as posting messages. Also, there can be more than one Co- SysOp. [See also SysOp]. country code - The code that the telephone company uses to desig- nate a certain country. If you need to call a BBS (or a person) in a foreign country, you need to dial the country code, then usually the city code, and then the phone number. CPS - See characters per second. CRC - Stands for Cyclic Redundancy Check. CRC is a system to make sure that data (usually a downloaded program) is as free as possible from error. crash - When a BBS is harmed in such a way that it is temporarily inoperable. The usual cause is that some files are destroyed, either by accident or by a hacker. Some people try to crash BBS's, a fact that most users (and especially SysOps) think is sad. crash recovery - This feature of some file transfer protocols allows a user to continue a download/upload that had been inter- rupted. With this system, a user will not have to receive the data that had already been sent before the disconnection. crippleware - This is software, usually distributed as shareware, but it is not a complete program. If it is a game, it might only let you play the first level. If it is a database program, it might only let you have 50 entries (whereas the real version would have more). CRT - Cathode Ray Tube. This is another name for a computer monitor. CTRL - The abbreviation for ConTRoL. This abbreviation is fol- lowed by a dash and then a character, such as CTRL-C, meaning the control character C. [See also control character]. CTRL-G - The control character G, which usually causes the com- puter to produce a beeping sound. CTS - This is when the modem lets the computer know that it can send information to the other computer. This is used only needed in half duplex mode. cursor - The marker that points out where text will next appear on your screen. It can be one of many things, usually a plain white or flashing square, or an underline. cyclic redundancy check - See CRC. cycling - When a light (such as the RD light) on an external modem continuous turns on and off. ---D--- dash - The character -. data - A group of characters that represents meaningful informa- tion. It can be in the form of anything ranging from bank ac- count numbers to all the words in a book. [See also information]. database - [1] A program that keeps track of data, such as the information contained on mailing labels. [2] A large group of data. The sum of the information that you can receive on exten- sive pay services such as CompuServe can be considered a data- base. database hack - A way that hackers attempt to gain access to someone's account. They create a list of common passwords (such as SECRET and MINE) and try every one on an account to see if it is the right password. Knowing about this method, an intelligent BBS user should realize that they should not use easy-to-guess passwords. data bits - [1] The number of bits that the modem uses to repre- sent one byte. This is usually 8, though it can be 7 since ASCII needs only 7 of the 8 bits. [See also format]. [2] the actual bits within a byte being sent through the phone lines. data byte - The byte of information that is to be sent over the phone lines. data carrier detect - See DCD. data communications equipment - See DCE. data compression - Some modems have the capability to 'squash' data so that it takes up less space. When another modem (with this capability) receives the data, it 'unsquashes' it to its original form. By using data compression, a modem can send information faster. [See also MNP-5]. data grade - A phone line that is set up by the phone company to be more convenient for data communications. However, it is rumored that data grade lines are no better than the alternative, voice grade lines. [See voice grade]. data mode - The mode that a modem is in where all information typed on the computer will be sent through the modem, and all information received by the modem will be placed on the screen. [See also terminal mode]. data modem - A modem that does not have the ability to send or receive fax transmissions. data set ready - See DSR. data terminal equipment - See DTE. data terminal ready - See DTR. DB-25 - The 25 pin plug that connects an RS-232C cable to the RS-232 port. DCD - Data Carrier Detect. This flag indicates whether the modem is connected to another modem. DCE - Data Communications Equipment. These are computer periph- erals that communicate. A modem is a DCE. [See also DTE decoy program - A program or text sent on mainframes and multi- line BBS's that simulates the log-on procedure. The unsuspecting user will enter his password, and the person who made the decoy program will get the password and can use the account. Only enter your password if you are sure you are giving it to the computer, and not a decoy program! default - A setting or an answer that is automatically assumed. If 80 columns is a default, then you only have to change it if you want something other than 80 columns. delay time - The time it takes between sending data on one com- puter and receiving a response. The higher the delay, the less efficient some file transfer protocol are. [See also protocol]. delete - To destroy information. Often you only delete one character at a time, such as when you are typing a message. To do that you usually use the DELETE key. demodulate - To convert the tones from the phone lines to data. destructive backspace - A term that indicates that your terminal program deletes the character the cursor is on when it receives the backspace character. [See also non-destructive backspace]. dial - To send out either tones or pulses that the phone company needs to understand what number you are calling. Most modems will dial automatically. dialout facility - A service where you call a computer, and from that computer you can call other computers. It is usually used with packet switching networks, where you can save money on long distance calls. dialup line - A telephone line connected to the telephone compa- ny. This is a regular phone line. [See also leased line]. dialup modem - A modem that is used over normal (dialup) tele- phone lines. dial modifiers - Any commands that are sent to a modem which change the way a phone number is dialed. For example: tone, pulse, and pause. dial tone - The sound that is on the phone line when the phone is picked up if it is ready to have an outgoing call made. Your modem, if it can dial, should understand this tone. dibit - Two bits sent simultaneously by a modem. A modem can operate at 1200bps and 600 baud. What happens is 600 times a second, the modem sends out a dibit (two bits). Therefore, it is sending 1200 (600 times 2) bits per second. [See also bps, baud]. digital - A system using discrete numbers to represent data. In computer systems, these are the numbers 0 and 1 (for binary). [See also analog]. DIP switch - DIP stands for Dual In-line Package. DIP switches are a group of small switches placed together, usually on elec- tronic equipment. Many modems have these. The switches can be changed to alter various settings. For example, one DIP switch on a modem may change the status of the DTR. disconnect - To hang up the phone and cause the connection be- tween you modem and another computer to be stopped. Most BBS programs have a way of disconnecting a user who has called the bulletin board. disk capture - This is when a communications program will save incoming information to the disk. This is useful if you are receiving a text file that you want to read later. door - A gateway that will allow a bulletin board to run a pro- gram while a user is using the BBS. The user can use most pro- grams that the computer can normally run. These programs can range from games to business programs. down - A word meaning that a bulletin board that is not working, so that you can not connect with it. This can mean that there was a crash, or it could simply mean that the SysOp is playing a game on his computer. Often a SysOp will leave a phone connected to his BBS line off the hook when he is using the computer so that you will get a busy signal. [See also running]. download - To receive a computer file from a bulletin board. It is usually a computer program, but can also be text. [See also upload]. driver - A program that will connect a program to a peripheral device (usually a modem or a printer). The driver will allow characters to be sent to or received from the device. Also, it will allow control of certain functions (such as letting a pro- gram hang up the phone with the modem) DTE - Data Terminal Equipment. This is computer equipment which is not responsible for communicating, for example, the computer itself and printers. [See also DCE]. DTMF - Dual Tone Multi-Frequency. This is used in tone dialing. It is a method where 2 distinct tones are sent for each digit dialed. DTR - Stands for Data Terminal Ready. DTR is a flag that, when set, indicates that the modem will be using its built-in terminal program. When running a BBS, this flag should be turned off (either with a DIP switch or a command sent to the modem). dumb modem - A modem that only sends and receives characters to or from the phone line. [See also smart modem]. dumb terminal - A keyboard and monitor that receive and send information either to or from another computer or a phone line. It is up to the other computer to do anything else, such as word wrap. duplex - The capability of both sides of a connection to send information. Full duplex is the same as duplex. When you are talking on the telephone to someone you are using duplex (you can both talk at the same time). [See also simplex, half duplex]. ---E--- EBCDIC - Stands for Extended Binary-Coded Decimal Interchange Code. It is a way of coding characters. It is similar to ASCII, but it uses 8 bits instead of 7. [See also ASCII]. echo - [1] A character that is sent back from a BBS instead of the one that is sent. For example, if you enter your password on a BBS it will often say `dots will echo', meaning that it will send a period for every character in your password (it is a safety feature). [2] When a bulletin board or your terminal program sends back the characters that you type. If the bulletin board does not send back the characters, your terminal program should print them to your screen as you type them. echomail - This is a technique used by many BBS's that will allow a message base to be shared by many BBS's. Usually late at night the BBS's will exchange any new messages. This way a user on one BBS can interact with users on other BBS's. edit - To change a message that you have created. editor - The part of the BBS that allows you to enter a message and edit it. electronic mail - See E-mail. E-mail - Electronic-mail. Messages that are sent to individual people. You choose who to send the message to and only that person receives the message. (Some BBS programs allow you to send bulk E-mail, which goes to more than one person, but the concept is still the same.) emotion icons - These are groups of several characters that are used to express emotion over the phone line. For example, :) is a happy face (when you look at it from the side). Similarly, :( is a sad face. emulate - When a communications program imitates a certain brand of terminal. encryption - Coding data so that people who are not supposed to see the data will not. EOF - Stands for End Of File. It is the character CTRL-Z, which marks the end of a text file. error - When there is line noise and one or more characters are changed. This is especially noticeable when downloading or up- loading a program. In this case the error must be detected. [See also line noise]. error control - The ability of a modem to notice errors in trans- mission, and have any incorrect data re-sent. [See also MNP 1- 4]. error correction - See error control. (Error control is a more correct term, since the modem does not correct incorrect data, it gets sent again). [See also MNP 1-4]. error free - When referring to data transmission, error free refers to data that is transmitted perfectly. This is actually an impossible situation, but it is possible to have data that is very, very close to error-free. ESC - See escape key. escape code - A sequence of characters (usually +++) that in- struct a modem to change from data mode to terminal mode, if they are typed with a certain amount of time between characters. [See also date mode, terminal mode, guard time]. escape key - The key marked ESC on a computer keyboard. It is often used to 'escape' out of a program or procedure in a pro- gram. Also, the ASCII character (ASCII 27) is used by ANSI to produce limited graphics. [Same as ESC]. [See also ANSI]. even parity - This indicates that the parity bit is always set such that the sum of the bits in each byte that is sent, plus the parity bit, is an even number. [See also parity, format]. executive mode - When a user is connected to a bulletin board, but the SysOp is controlling the bulletin board. The most common use of an executive mode is when the SysOp validates users with- out the user having to hang up. exit - See logoff. expert mode - Some BBS's have this feature, where a user who feels he knows the system well can save time by not having menus sent to his system. If he forgets some commands that are avail- able, he can have the menu appear. Otherwise, the menus will not appear. extension - The extension of a filename is the last three charac- ters, which are separated from the rest of the filename by a period. For example, the filename SPREDSHT.WKS has the extension "WKS". [See also archive]. external modem - A modem that is located outside of the computer. It is hooked up to the computer with a cable, most commonly an RS-232C cable. [See also internal modem]. external program - A computer program that is not part of another program. When BBS software runs a program that is separate from it, it is called an external program. [See also door]. ---F--- fall-back - The ability of a modem to change to a lower speed when there is a problem communicating at the higher speed (usual- ly line noise). [Same as auto fall-back]. fall-forward - This is when a modem will change to a faster speed if line conditions improve after a fall-back occurs. fax - A copy of a piece of paper that is sent over the phone lines by a fax machine. Some modems also have fax machines built in them, so that they can send and/or receive faxes. FCC - Stands for Federal Communications Commission. This is the government agency that is responsible for making sure that phone lines are being used correctly and that radio interference is as close to nonexistent as possible. FDM - Frequency Division Multiplexing. A way that some modems transmit full duplex information, by splitting the telephone bandwidth into two sections. One is used to receive data, the other is used to send data. This method can be used at speed of up to 2400BPS. feature negotiation - This is when a modem can determine the best protocol to use when connecting to another modem. This includes the best speed, error control, and data compression. feedback - A message that is sent by a user to the SysOp of a bulletin board. While it is meant to be a way for the user to let the SysOp know of any complaints or compliments they may have, it is more often a convenient way of sending E-mail to the SysOp. file - Any data that is stored by a computer in a form that is accessible by disk. It can normally a program, text, or data for a program. Most BBS's will allow you to send or receive a file. [See also download, upload]. filter - When a communications program or a BBS program take out certain characters or words and don't accept them. For example, a bulletin board program may filter out CTRL-G's so that the SysOp does not hear the beeping. Also, some BBS programs have the ability to take out obscene words from messages. [See also profanity filter]. filter device - A piece of hardware which goes between the modem and the phone line of a BBS or mainframe. When a user calls up, they will either have a voice or computer connection that asks them for a special password before they can gain access to the main computer system. This makes it more difficult for hackers to get into the system, but makes more of a burden for the legit- imate users. flash - On a normal telephone, this is when you quickly push down and release the off-hook button. This is often used for call waiting. Many modems have a command that will simulate this. flag - A piece of information that is either TRUE or FALSE. It is used in some bulletin board security systems to indicate whether the user has access to certain parts of the bulletin board. It is also used by modems for certain indicators such as DTR. flow control - A method of controlling when information is sent. One method is Xon/Xoff, where a BBS will send information until your computer sends an Xoff (CTRL-S). It will resume sending information when you send an Xon (CTRL-Q). format - Information such as `8N1' that describes the way that your computer and a bulletin board should be connected. The first digit is normally 7 or 8, the number of data bits. The second character is a letter describing the parity (N for None, M for Mark, S for Space, O for Odd, and E for Even). The last number is the number of stop bits. 8N1 is most often assumed. Data is sent as follows: Start bit (0) - 7 or 8 bits of data - (parity bit, if used) - stop bit (1) - (gap bits, if used) [Same as settings]. forward - When pertaining to E-mail, it means to send E-mail that you received to someone else. framing bits - Bits that are used to separate characters. The bits themselves are not used for information. freeware - Computer programs that are copyrighted, but they may be legally copied if there is no payment involved. They are almost the same as public domain programs, but public domain programs are not copyrighted and may be sold for payment. Free- ware programs often can not be changed when they are distributed. [See also public domain, shareware, copyright]. frequency division multiplexing - See FDM frequency shift keying - See FSK. frequency spectrum - A range of frequencies. Similar to band- width. FSK - Frequency Shift Keying. This method that low-speed modems use to transmit information over phone lines uses 4 frequencies, which are used to represent 0's and 1's for both sending and receiving. These modems can only operate up to a frequency of 600BPS at full duplex (or 1200BPS at half duplex). full duplex - See duplex. full flow - See streaming. ---G--- gap - A series of 0's that will are sometimes sent between data bytes over the phone lines. garbage - Unwanted characters that appear because of either line noise or incorrect settings. [See also line noise, format]. general file - Any kind of text on a bulletin board that is not specifically E-mail, a bulletin of any sort or a message. Usual- ly they are long files for the user's information. Some examples of general files are: a file containing more information on the bulletin board program, a newspaper article about a controversial issue, and an article that explains how to make your own disk drive. global scan - When a bulletin board goes through all the messages on all boards to check for new messages that the user has not yet read. This is very useful as it prevent you from having to go through each board to check for new messages. goodbye - The command on a BBS that will log you off. group III - The standard for fax communication. guard time - When the escape code is sent to your modem, the guard time is the amount of time that can occur between charac- ters of the escape code. If a longer delay occurs, you can not switch to terminal mode. [See also escape code, data mode, terminal mode]. guard tone - A tone that is sometimes sent over the phone line for echo suppression. 1800 Hertz and 550 Hertz are sometimes used. guest - When a user is just looking at a bulletin board and does not want to receive an account there. The user usually has the same privileges as a new user who has not yet been validated. Quite a few bulletin board programs allow guests. This is a good feature, since the SysOp does not have to validate users who will not be calling the board more than once or twice. ---H--- hacker - [1] A programmer who likes to experiment with computers (this is the type of person who often will not read the documen- tation to software before using it, so he can figure out how to use it by himself). [2] A person who attempts to abuse the privileges of computer BBS's and other services. His activities may range from getting and exploring an account he is not sup- posed to have on a mainframe computer to attempting to crash a bulletin board. These people are unwanted by most BBS's. They are often not malicious. The media sometimes confuses them with phreakers [See also phreaker]. half duplex - This is a mode which allows only one computer at a time to transmit information. When one computer is finished, the other then can start to transmit. [Same as simplex]. hand-shaking - The process of establishing an electronic link between two computers. Handshaking can let both computers know the speed they will be using, as well as other information. handle - See alias. hang - When a bulletin board all of a sudden starts to do noth- ing. That is, it will not accept calls or let the SysOp type anything until the computer is turned on again. hang up - When someone closes a switch which stops a telephone connection. This either happens when someone puts a telephone receiver into its cradle or when the person instructs the comput- er to hang up. hardware error control - This is when error control is done by the modem, not the communications program. [See also error control]. Hayes compatible - Any modem which operates in the same way as the modems developed by Hayes. Most modems up to 2400bps are Hayes compatible. Hayes AT command set - This is the set of commands used to oper- ate Hayes modems and Hayes compatible modems. Almost all of the commands start with AT. help file - Many BBS systems will include information of how to run the system in case you are having troubles. Often just pressing H at the main menu will show you the information, but with some well-designed (there's a hint of sarcasm there in case you didn't notice it) systems you have to find the help file somewhere, sometimes amidst the files to be downloaded. host - The computer that is being used to send and retrieve information from other computers. Every BBS is a host, and so are pay services. host program - A computer program that allows your computer to accept incoming calls. If you want to do anything more than that, such as record information or print it out, you usually have to do the programming yourself. hot-keys - A term which means that you only have to press one key at a menu, rather than several. You don't even have to hit the return key. Usually you can do this while the menu is being sent to your computer. HST - High Speed Technology. A 9600bps protocol developed by US Robotics. It allows for 14400bps one way, and 450bps the other way. The two computers can switch when one has more information to send than the other. It is not compatible with the CCITT protocol. hyphen - The character -. ---I--- IBM graphics - On IBM-PC computers, there is a group of "graphic" characters that can be used. Some BBS's will send these graphic characters if requested. Most non-IBM computers will not recog- nize these characters. These characters have their 8th bit set to 1. ID number - The unique number that a computer bulletin board may assign you. If the BBS uses ID numbers, you need to remember this number and your password in order to access the bulletin board. Same as user number, account number. idle time - When a computer is not being used. This refers to either a computer running a BBS that is not busy, or a caller that is not typing anything or receiving anything. Some BBS's will hang up a user if there is a certain amount of idle time (such as a minute). incoming - Information that is being sent to the computer which is being referred to. Therefore, incoming data it the data that is being sent to your computer. information - Any data that is sent between computers. Data usually refers to numbers and small pieces of information. Information is usually used for larger things, such as text files. initialize - To set up either hardware or software to work cor- rectly with your system. Many modems have to be initialized each time they are used so they `know' what to expect. When your software initializes your modem, it may tell the modem to expect 2400 baud and no parity, as well as the fact that you do not want any information to echo on your screen. interdigit interval - When pulse dialing is used, you need a certain amount of time free of "clicks" so the phone company knows that the digit is finished. When you are dialing on a rotary phone, you don't need to worry about this because the time it takes to turn the dial is sufficient. A modem that sends pulse codes must wait a specified amount of time before going from one digit to the next in a phone number. A value between 1/2 second a 1 second is usually used. internal modem - A modem that is `hidden' inside your computer. Outside of your computer you will only see the phone cord. An internal modem can either be on a peripheral card that is placed inside your computer, or it can be built into your computer. interrupt - An interrupt, as far as modems and computers are concerned, is an electronic signal that tells the computer that something important is happening. Most modems can be set up by software to send an interrupt every time a character is received by the computer. When operating at fast speeds, this makes sure that the computer doesn't miss characters as it is printing them on the screen or saving them to a disk. ---J--- jack - A small plastic box that your phone cord fits into on your wall. This box converts the three wires that are inside the phone cord into 3 separate wires that the phone company uses to make your phone calls. jump - A command used on some BBS's to go from one board on a BBS to another. ---K--- K - When K is placed after a number, it means 1024 times that number. If you computer has 128K that means that it has a little more than 128000 bytes of memory. Often telecommunications software will tell you that you have a certain amount of free memory to use as a buffer. Kermit protocol - An almost error-free file transfer protocol usually used for text transfers. It was developed at Columbia University. [See also protocol]. keyboard macro - A macro that will allow you to hit one or sever- al keys and have the program act as though you had typed a lot directly from the keyboard. kill - When referring to a message on a bulletin board, it means deleting the message from the board. Usually you can only delete the messages that you write (unless you are a SysOp). --- L --- LAN - Local Area Network. This is a group of computers that are all connected. Usually, there is one computer that controls all peripherals (such as printers and a hard disk drive). The other computers are linked to the controlling computer, which lets the other computers take turns using the peripherals. LAPB - Link Access Procedure Balanced. This is a form of error control for X.32 packet switched networks. LAPM - Link Access Procedure for Modems. A type of error control used by some modems. It is included in the V.42 protocol (V.42bis also includes it, since V.42bis includes all V.42 error control methods). It is NOT a compression method, even though some modem manufacturers advertise it as such. [See also V.42]. leased line - A telephone line that directly connects two comput- er. It is usually rented from the telephone company. A leased line doesn't have some of the electronic restrictions that a dialup line has, so data can be sent faster. However, data can therefore only be sent between the two computers. [See also dialup line]. leave (a message) - See post. leech - A term used for a person who downloads a lot from a BBS, and does not upload much or use the message bases. left-brace - The character {. It's not used often. left-bracket - The character [. letter - [1] The characters A-Z (uppercase or lowercase) [2] Another term for a message posted on a BBS. LF - Line Feed. This is a control character (ASCII 10) that is used on some computers and printers to move down one line (on the screen or paper). It is usually used right after a carriage return. LHARC - A program that will un-arc archives with the extension "LZH". [See also archive, LZH]. line - [1] A row of characters on your screen, for example, many computers have screens with 25 lines. (See also columns). [2] The connection between your computer and a BBS. Most commonly used in the term "line noise." [3] A phone line connected to a BBS. For example, a BBS might advertise that it has "4 lines," meaning that 4 people can call the BBS and use it at the same time. [Same as node]. line delay - See delay time. linefeed - See LF. line noise - This is interference on the telephone lines. It will cause a character or many characters of garbage to appear on your screen. In general, the higher the BPS of your modem, the more line noise will appear. link access procedure - See LAPM, LAPB. local - On a computer that is running a BBS, there are 1 or more phone lines connected to it. However, the SysOp can usually use the BBS, too, from the keyboard. This is considered a local connection. local echo - This is when a communications program will send information (either that you type or from a file) to your screen, as well as the other modem. Usually this is not the case, and the BBS you are connected to will send the information back to you, and only then will the communications program print what you typed on your screen. log - A log is a file that keeps track of some kind of use. In a communications program, it might keep track of what BBS's you call. A BBS can keep a user log, which is a file that indicates which users called up and when. [See also user log]. logic bomb - This is part of a software program that will do something malicious. For example, the author of a BBS program might have the program set up so that if he enters his initials in a certain point while the program is running, it will destroy the files on the BBS. logoff - To leave a BBS. When you choose to logoff, the BBS will usually ask if that's what you really want to do, then it will hangup. logon - The process of connecting to a BBS. The is what occurs after you have called the computer and the phone starts to ring, but before you actually start using the BBS. "Logon" can also include the process of entering your name and password (which is also called sign-on). [See also signon]. lowercase - The letters that are normally used, such as in this sentence. The other kind of letters are UPPERCASE. [See also uppercase, capitals]. LZH - This file extension refers to an archive that was com- pressed with the program LHARC. You need to get that program from a BBS before you can un-archive the program. [See also archive, unarchive, LHARC]. --- M --- macro - A series of instructions or text that can be entered by hitting a couple of keys. For example, a communication program might let you enter your user name and password just by hitting CTRL-N. [See also trigger character]. mainframe - A large computer that many people can use at the same time. Usually a mainframe computer is owned by a large company, and it will has a lot of memory and storage for its users. Some mainframes have phone lines connected to them so that employees (or other authorized people) can use the mainframe from home. manual-syncing driver - This is when a BBS program can not deter- mine directly what the user's bps rate is, and the user must hit the return key several times before the BBS can figure out the user's speed. mark - When you are looking at the titles of messages to read, some BBS programs will allow you to choose certain ones you want to read. This is called marking. mark parity - This is when the parity bit is always set to a binary 1. [See also parity, format]. menu - A list of option that you can choose from. A BBS might have a menu that lets you choose from reading messages, download- ing, or logging off. In reality, there would be many more op- tions. message - Any text that is left in a message base on a BBS. These can range from questions for other users to answer, to information on new computer programs, to just about any topic you could imagine. message base - A group of messages on a certain topic. For example, a BBS might have a message base for general messages, computer-related messages, and social information. Some BBS's have dozens or even hundreds of message bases. minicomputer - A scaled-down version of a mainframe. A mini computer usually has many terminals connected to it, and can run many programs at the same time. It is more powerful than a microcomputer. MNP - Microcom Networking Protocol. A type of error control and data compression, created by Microcom, that many newer modems use. It is built into the modem, unlike software error correc- tion in file transfer protocols. There are different MNP levels. Levels 1-4 are error control protocols, and level 5 is a data compression protocol that can compress data to about 50% of its original size. A modem with MNP-5 also has MNP-4. MNP 1-4 is also included in the CCITT V.42 error correction system. mode - The state that a computer or a program is in. For exam- ple, a computer can be in a text mode, and a communications program can be in a chat mode (which operates differently than the normal mode). modem - MODulator/DEModulator. This is a computer peripheral which allows a computer to communicate over telephone lines. This is the heart of computer telecommunications. The main factor that differentiates modems is their speed, measured in BPS. modify - To change a message after you have typed it. modulate - When a modem changes information from computer bits into tones that can be transmitted over the phone lines. [See also PSK, FSK, FDM]. MTA - Message Transfer Agent. This is what moves data across a network under the X.400 electronic mail system. [See also X.400]. multiple-speed - This refers to a modem that can operate at several speeds. Most modems are capable of doing this. While a modem may be listed as having a speed of 2400BPS, it most likely can operate at 1200BPS and 300BPS. multiple-state modulation - When a modem sends more than one bit per baud. multi-line BBS - A BBS that has more than one line or node. ---N--- NAK - This control character (CTRL-U) is sometimes used by commu- nications or BBS programs (usually in file transfers) to indicate that the information it received was bad. NAK stands for Nega- tive AcKnowledgement. network - A group of BBS's that are "linked" together. This means that the BBS's share messages and sometimes files. Usually the BBS's will call each other late at night to get the messages and files. [See also echomail]. new user - When you use a BBS, usually you will have the status of new user for the first few calls, until the SysOp verifies your account (at which time you will normally be considered a registered user). A new user usually has less privileges, such as not being able to download programs. news - Some BBS programs will have announcements that are shown when you log on to the BBS. These are often referred to as news, since they often inform you of changes to the BBS. [Same as system news]. next - A command in some BBS programs that will let you view the next message in a list. node - A line on a BBS. BBS's sometimes advertise having a certain number of nodes, meaning that that number of people can use the BBS at the same time. [Same as line. Line is more common than node]. noise - See line noise. non-destructive backspace - This is when a communications program will not delete any characters on the screen when the backspace key is pressed. null character - The ASCII character 0, or CTRL-@. This charac- ter usually will not be printed on the screen. It was originally used when communications programs were slower and could not receive information as fast as it was sent, so BBS programs would send these characters in between lines to slow down how fast the information was being sent. null modem - A special connection between two computers that will make the computers think they are hooked up to a modem, so that they can communicate to each other. ---O--- odd parity - This indicates that the parity bit is always set so that the sum of the bits in a byte, plus the parity bit, is an odd number. [See also parity, format]. off hook - The state that your telephone is in when you pick it up. In non-computer life, it usually means when the telephone connection is accidentally disconnected, such as "Someone must have left the phone off the hook." A modem that takes the phone "off hook" is taking control of the phone line, and it will usually then dial a phone number for you. When a telephone line is "off hook," you are not able to receive calls from other people. (See also on hook) off hook button - This is the button on a real telephone that is depressed when you put down the received. It signals the phone company that your phone is off hook, and ready to receive calls. off line - When your computer is not connected to another BBS. (See also on line) on hook - When your telephone is not being used, and it is ready to ring if someone calls. (See also off hook) on line - When your computer is connected to a BBS. For example, some communications programs will keep track of how long you have been on line. This lets you know how long you have been connect- ed to the BBS. on-line conference - This is when a group of people "get togeth- er" and have a conference using their computers. Some of the major on-line services do this. [Same as real-time conference]. on-line games - Any game that is played on a BBS. Sometimes they are played in real time against other players who are using the BBS at the same time, and sometimes they are played by making a move and waiting for the opponent(s) to make their move. [See also Role Playing Game]. on-line service - While this can refer to any computer that is hooked up to the phone line, it usually means a pay service such as Compuserve or GEnie. originate - To call another computer and connect to it. The originating computer is the one that placed the telephone call (as opposed to the BBS, which is the answering computer). originating computer - The computer which dials another computer. This is most likely referring to your computer (unless you have a BBS, or other people are calling your phone number, and you have your computer's modem answer the phone). [See also answering computer]. originate frequency - This is the frequency of the carrier that is used by the modem that places a call to another modem. [See also answer frequency]. originate mode - This is when a modem is ready to place a call, rather than accept an incoming call. ---P--- packet - [1] A group of bits sent by a modem that comprise a byte of information. [2] A group of bytes sent by a file transfer protocol. pad - This happens when a file that is being transferred ends in the middle of a block of data. The communications program must add blank data to fill up the block. This is called padding. [See also protocol]. page - (noun) A page in one screen's worth of information. Many BBS's will automatically wait for you to press a key after it has sent you a page of information. (verb) to alert the SysOp that you would like to speak with him. Many BBS's will allow you to do this, and it will make beeping sounds so that the SysOp will know you want to talk to him. [Same as yell]. [See also chat]. PAK - [1] The extension for files archived with the program of the same name. You need the program PAK to un-arc an archive with this extension. [2] The program itself. [See also archive, unarchive]. parallel - This is when a computer sends data one byte (or any number of bits other than one) at a time. This is faster than the alternative, serial. [See also serial]. parity bit - Most modems have the capability to send an extra bit for every byte sent, which is used to help sense errors. This is called the parity bit. It can be set to no parity, mark parity, space parity, odd parity, or even parity. Most BBS's use do not use a parity bit. [See also format, mark, space, odd, even]. password - A special code that only you should know. This code will allow you to gain access to your account on the computer. Different BBS's have different rules as to how long your password can be and what characters can be used. You should not use a password that is easy to guess (such as your name, or "password"), because a hacker might try to gain access to your account by guessing your password. pause - On most modems, you can send the modem a command that will pause at some point while dialing a number. This can be useful on PBX systems, if you have to wait for a dial tone. PBX - Private Branch Exchange. This is the telephone system that many offices have, allowing for extensions for each telephone, and a connection to the main telephone system. PC-Pursuit - A packet switching network that allows people to save money on long distance calling. phase shift keying - See PSK. phone number - A number identifying a specific phone line. In the United States, a phone number consists of a 3 digit area code and a 7 digit number. If you call BBS's in other countries, there may be a specific country code and city code that is part of the phone number. You can usually find these codes in a phone book. A BBS will usually ask you to tell it your phone number before you can be a registered user. phreaker - A person who spends a lot of time trying to find out as much as possible about the telephone company, and how it works. They often try to find out ways to make long distance calls for free. Some steal calls from telephone credit card users, some steal calls from the phone company directly, and others don't make "free" long distance calls. They are sometimes confused with hackers (See also hacker). pick up - To pick up a carrier is when the 2 modems recognize each other's signals over a phone line. After this point the two computers can communicate. ping-pong - A 9600bps and 4800bps protocol developed by Hayes. It features fast turnaround. pins - The ports on the back of your computer and an external modem will have pins. Each pin has a certain function, such as letting the computer know that the modem is online. PKARC - The program which will make an archive with the extension "ARC". [See also archive, unarchive, ARC]. PKUNZIP - The program which will un-arc a file that has the extension ZIP. [See also unarchive, archive, ZIP]. PKXARC - The program which will un-arc an archive created with PKARC. [See also unarchive, archive, ARC]. PKZIP - The program which will create an archive with the exten- sion "ZIP". It is one of the most popular archive programs. [See also archive, unarchive, ZIP]. pocket modem - An external modem that is small enough to be portable. It usually either uses a battery for power, or it can get its power from the phone line. poll - [verb] The process when a computer checks whether a pe- ripheral or another computer has data to send. [noun] See vote. post - To save a message that you have written on a BBS so that other people can see it. private - When referring to a message, it means that only a specific person or several people that you specify can view the message. [See also public]. private branch exchange - See PBX. privileged - Some BBS's have a privileged user level, where the user can do more than a regular user. For example, they may be able to download more programs than regular users. [See also user level]. profanity filter - Some BBS's have a this special function that will take out any of a number of specified words from messages that people leave. That way, the BBS will automatically keep itself "clean," even if users try to leave swears in their mes- sages. prompt - A character or group of characters that are meant to remind the user of a BBS that he needs to enter some information. It might say "What now?" or it might list the name of the message base the user is currently in, or a list of possible commands. protocol - [1] When referring to file transfers, a protocol is a method of sending and receiving a program. There are many meth- ods available, each with different advantages and disadvantages. [See also Xmodem, Ymodem, Zmodem, Kermit]. [2] Protocol is also used to describe the way that hardware error control is managed. PSK - Phase Shift Keying. In this method of modulation/demodula- tion, there are two frequencies used (usually 1200 Hertz and 2400 Hertz). There are 4 different phase angles (0, 90, 180, and 270 degrees), representing dibits 00, 01, 10, and 11. This is usual- ly used for 1200bps transmission. Note that the baud rate using PSK is really 1/2 of the bps rate, since 2 bits are sent at a time instead of one. [See also modulation, demodulation]. PSTN - Public Switched Telephone Network. This is the regular phone lines that just about everybody uses. public - When referring to a message, it means that the message is available for everyone to see. [See also private]. public domain - A program that is in the public domain usually has no copyright, and can be copied legally by anybody without payment. BBS's often have public domain software available for people to download. [See also shareware, freeware, commercial software]. public messaging - A fancy term that means to read and/or leave messages in a message base. public switched telephone network - See PSTN. pulse dialing - A method that some phones use to dial numbers. It involves a series of "clicks." Most modems support this type of dialing, which is the only type available in some remote areas. The other method of dialing is tone dialing. [See also tone dialing]. ---Q--- quickscan - An option used by some bulletin board programs which will let you check several messages bases to see if there are any new messages. ---R--- rack mounted modems - Some multi-line BBS's use rack mounted modems, so that the modems can be easily and safely stored. RD - Receive Data. This is the wire in an RS-232 cable that receives data. real-time conference - See online conference. receive - To transfer information from another computer to your computer. To receive a file is the same as downloading the file. [See also send]. receive sensitivity - See carrier-detect threshold. registered user - This is the most common user level on most BBS's. It usually allows reasonable usage of the BBS (perhaps it will give you a time limit of 45 minutes per day, and let you download up to 200K of programs). [Same as regular user]. [See also user level]. regular user - A user of a BBS who has the normal user level. [Same as registered user]. remote - A computer in a different location. For a BBS, the user is at a remote location (since they are connected by the phone line, and not right there). request to send - See RTS. reread - After a message is sent to your computer from a BBS, the reread command will send the message again. This can be useful if the message is long. reset - A modem can be reset. This will change any options (such as parity and speed) to the values that they have when the modem is first used. This can be useful if you change some values for the modem and aren't sure what they do, and then the modem won't work. Resetting the modem will fix everything for you. result codes - These are either numbers or words that the modem sends to the communications program (which will usually print them to the screen for you to see) that indicate how the modem responded to an action you requested. For example, if you tell the modem to dial a number, it may respond with "CONNECT 1200", which is a result code that means that the computer dialed the number and connected to a computer on the other end. return - ASCII character 13. This is the key marked "RETURN" or "ENTER". It will advance the cursor to the next line. On some printers, it will just move the print head to the left hand side, and needs a linefeed to move to the next line. [Same as carriage return, reverse - When you are in a message base, you may find this command which will allow you to read messages is backwards order (from newest to oldest messages). right brace - The character }. right bracket - The character ]. ring - When someone calls you on the telephone, the sound that your phone makes is called a "ring." Also, when you call someone (or a computer), it will ring before they pick it up. This indicates that the number is not busy, but nobody has picked up the phone yet. ringback - The sound that you hear over the phone that indicates that the phone is ringing on the other end, and not busy. It sounds a lot like a phone actually ringing. RJ-11 - This is a normal phone jack. Modems usually have 2 jacks like this, one to connect to the phone line, and the other to connect to a telephone (that you can use when the modem isn't being used). RPG - See Role Playing Game Role Playing Game - Some computers don't act as places to leave messages or programs, but instead let you play a game. On these computers, you have a character and call up the computer to move around in a world with other characters (other people who call up), and you interact with them (for example, you may try to kill the character). [Same as RPG]. rotary - A phone that dials with the pulse method. [See also pulse dialing, tone dialing]. RS-232 - The name of an interface that connects a computer to a modem (or other serial device). The interface consists of 25 wires. Some computers and peripherals have an RS-232C port, which allows you to connect them with a simple cable. running - Working. If a BBS is running, then it is working correctly and people can call it. [See also down]. RTS - Request To Send. This is when the computer tells the modem that it wants to send information to the other computer. It is only used in half duplex mode. ---S--- scan - To look through messages or file descriptions to either find news messages/files or look for certain key words within the messages or descriptions. screen width - The number of characters that a computer can display on one line. On most modern computers, it is 80 charac- ters. [Same as video width]. [See also columns]. script language - Many communications programs allow the user to write a program, or script, which allows them to use the communi- cations program without actually typing anything. It is often used to call BBS's late at night to download programs or look for new messages. sector - A unit to measure storage space. It usually refers to 256 bytes. It is rarely used anymore. security level - Some BBS programs will have different user levels, usually numbered, which allow different levels of access. For example, 0 might refer to an unregistered user, 10 a regis- tered user, and 99 for the SysOp. Each would have different levels of access on the BBS. [Similar to user level]. send - To transfer information from one computer to another. To send a file is called uploading the file. [See also receive]. serial - The method that a computer uses to send and receive data one bit at a time. Contrast this to parallel. [See also paral- lel]. serial port - A port on a computer that is used to transmit and receive data in a serial fashion (one bit at a time). [See also RS-232]. settings - See format. set-up - (noun) - Information that a BBS has about your computer. (verb) - To give the information about your computer to a BBS. This information usually includes screen width, whether you want hot-keys, and other miscellaneous information. shareware - programs can be distributed freely, but you must pay for these programs if you use them. They usually allow you to try them for a specified period of time, and then either pay for them or get rid of the program. Many BBS's have shareware pro- grams that you can download without paying the BBS, but you must remember that if you use a shareware program you are supposed to pay for it. [See also public domain, freeware, commercial soft- ware]. shell virus - A virus which places itself either before or after a program on a disk or in memory. It can be easy to detect such a virus, since the length of the program will be longer after the virus hits than before. [See also virus]. SIG - Special Interest Group. This is similar to a message base, but it may also contain files. It is generally used on large services, such as CompuServe. [See also SIGop]. SIGop - The coordinator of a SIG. This person is responsible for checking messages to make sure that they pertain to the topic. [See also SIG]. sign-off message - A message that is displayed when you log off a BBS. Often the message will include the numbers of other BBS's, and in some cases the BBS will allow you to leave a message for the next user to call the BBS. sign-on - The procedure of letting a BBS know who you are. This involves giving the computer information such as you user number, name, password, and sometimes even phone number. sign-on message - A message that is displayed by a BBS after you sign on. Often the news will go here. On some BBS's you can leave a sign-on message for the next caller. [See also news]. simplex - See half duplex. smart modem - Originally the brand name of a modem, it refers to a modem which has capabilities which make it 'smart'. Most modems now sold are considered smart. Basically, it means that the modem has many features. smart terminal - A terminal that is capable of certain editing features. [See also terminal, terminal emulation]. space parity - This is when the parity bit is always set at a binary 0. [See also parity, format]. special interest group - See SIG. speed - This refers to the BPS of a modem. The most common modem speeds are 300BPS, 1200BPS, 2400BPS, and 9600BPS. start bit - This bit indicates that the data byte will be follow- ing. It is always a binary 0. [See also format]. statistics - Any information that a BBS keeps on its users. Some BBS's keep track of how many messages a user posts, how many programs the user uploads or downloads, and even how many times the user has called. stats - See statistics. status line - In communications programs, sometimes the bottom line of the screen will contain a status line, which has informa- tion such as the speed of the modem, the parity, how long you have been connected to a BBS and other such information. stop bit - When a modem sends a byte of data, it usually sends one or two bits after the data byte, before the next byte is sent. These bit(s) are called stop bits. They are always a binary 1. [See also format]. streaming - When a file transfer protocol sends data continuous- ly, without waiting to make sure there are no errors. A stream- ing protocol should check for errors, but if an error occurs the file transfer should be stopped. A streaming protocol should only be used with modems that have hardware error control. [See also Ymodem-g, protocol]. [Same as full flow]. streaming Ymodem - See Ymodem-g. STU-III - Secure Telephone Unit, generation III. This is a system used by the government that makes voice and data calls much more secure. subboard - A term referring to different message bases with specific topics. This term is rarely used any more. subject - Most BBS's require that you leave a short description about any messages that you post on the BBS. This description is referred to as the subject of the message. [Same as title]. subop - A term used for the operator of a subboard. Some BBS's would allow a person besides the SysOp to control a message base. This person would be able to kill any messages that he/she felt were inappropriate. synchronous communication - With synchronous communication, data bytes are not marked with a beginning and end, but instead are sent at a specific interval. When computers send data to modems, it is synchronous communication. When modems send the informa- tion they get from the computer, the modem will add start and stop bits to identify the bytes. That is asynchronous communica- tion. [See also asynchronous communication]. SysOp - Short for SYStems OPerator. This is the person who is in charge of a BBS. He has the power to change anyone's user level, delete users, delete or edit messages. Usually this is the same person who paid for the BBS equipment and pays for the phone line. SysOp window - Some BBS programs have an area of the computer screen (on the computer that the BBS runs on, not the user's screen) that gives information about the user, such as his pass- word, where he is from and his phone number. This is called the SysOp window, and is for the convenience of the SysOp. [Similar to top of screen display]. system - Your computer. When a BBS asks for your system configu- ration, it is referring to information about your computer, such as screen width. system files - Any computer files that are used by an operating system, or in the case of BBS's, files that are used by the BBS program that do not get changed. system news - See news. ---T--- tab - The key on your keyboard that will move the cursor forward about 5 spaces. It is not an ASCII character (it is similar to a function key, since it does not output a single character). TCM - Trellis Coded Modulation. This is a form of error control used on some modems. TD - Transmit Data. This is the wire in an RS-232 cable that is used to transmit information. Telco - Abbreviation for Telephone Company. telecomm - Short for telecommunications. See telecommunications. telecommunication(s) - This word has no precise definition, but is frequently used. Its definition ranges from "any form of communication over a distance" to "any communication by electric means" to "two computers 'talking' to each other via modems." Methods of communications that probably are considered telecommu- nications: BBS's, telephones, TV's and fax machines. The word can be used either in singular or plural. Telenet - A packet-switched network that is used for PC-Pursuit, which is operated by U.S. Sprint. term program - See terminal program. terminal - A CRT and keyboard that are connected to either a computer or a modem. [See also smart terminal]. terminal emulation - When a communications program can simulate the operations of a smart terminal. terminal mode - Some modems have a built in terminal program. On these modems, if that program is running, the modem is said to be in it's terminal mode. terminal program - A program that allows a person to use a modem. It is generally very limited. A communications program is a more advanced version of a terminal program. Usually a terminal program will simulate a specific brand of terminal. [Also called term program]. terminate - To disconnect with another computer. This is some- times listed as a command in menus on BBS's. text file - Any information that can be read, and is stored in a computer file. A text file can be any kind of information, such as a description of a computer program. throughput - The effective modem speed after data compression is accounted for. For example, a 2400bps modem that has a data compression method that on average halves the amount of data that needs to be sent, has a throughput of 4800 bps. tilde - The character ~. time limit - Most BBS's have a time limit, where you can only be on the BBS for a certain amount of time. On some BBS's you can only be on for a certain time each time you call, on others there is a daily time limit. time out - BBS programs often will disconnect a user if he doesn't type anything for a certain amount of time. Time out occurs when the time limit is reached and the BBS program hangs up on the user. This is done so that users do not tie up the BBS, which would mean that other callers could not get through. timing signal - A signal sometimes sent by modems over the phone line that let the receiving modem know when a byte of information starts. title - See subject. tone dialing - This is a method that a phone or modem uses to dial a phone number. It uses one tone per numeral to be dialed. [See also pulse dialing]. top of screen display - Some BBS's have this display on the top of the screen of the computer running the BBS. This will show the SysOp certain information about the user, such as his phone number, how many programs he has downloaded, etc. [Similar to SysOp window]. transfer - To send a computer program from one computer to anoth- er. [See also download, upload, protocol]. trapdoor - This usually refers to a BBS program (or a mainframe that you call up) that has a special code that can be entered to give you high access. Usually it is entered as a user name and password when logging on. These are undocumented by the program, and usually created by the programmers so they can gain access to any computer running their BBS program. Hackers try to find trapdoors, but they are usually not created by hackers. (Some other kinds of software have trapdoors, such as video games, which might have trapdoors to give you extra lives). Trellis-coded modulation - See TCM. trigger character - This is a character that, when pressed, starts a macro. [See also macro]. trojan horse - A trojan horse is a program within another pro- gram, usually on a mainframe or a computer running a BBS. The original program looks innocent, but when run it will trigger the trojan horse, which will usually try to gain access to the main- frame computer system or BBS. TTY - A TeleTYpe machine. It is a keyboard and a printer com- bined in one unit. It is hooked up to another computer. TTY mode - This is when a communications program emulates a TTY machine, which only involves printing characters and recognizing the linefeed, carriage return and backspace characters. [See also TTY]. Tymnet - A packet-switched network. type-ahead buffer - Some BBS programs let you type characters to the BBS, even while it is sending information to you. When it is finished sending the information to you, it will then act on the information you sent. The type-ahead buffer refers to the proc- ess, and the space in the BBS computer's memory where the charac- ters are held. ---U--- UA - User Agent. It is the program that people use to create and read messages under the X.400 system. [See also X.400]. UART - Universal Asynchronous Receiver/Transmitter. This is a device in a modem that will change serial data (they way data comes in over the phone line) to parallel, and vice versa. [See also serial, parallel, 16550 UART]. un-arc - See unarchive. unarchive - To take out the files from an archive. [Same as un- arc]. [See also archive, ZIP, ARC, PAK, LZH]. unattended - This mode is available on some communications pro- grams. It will let your computer wait for a telephone call from another computer, and will let the person using that computer access your computer (usually to download or upload programs). It is call unattended because you don't have to wait for the person to call, it will automatically answer when they call. underline character - The character _. underscore character - Any character (although almost always the underline character) that is used for underlining. When this method is used, the text to be underlined will be sent (usually to a printer), and then backspaces will be sent, and then the underscore character will be printed over the text, so it looks like it is underlined. upload - To send a program from your computer to a BBS. [See also download, transfer]. uppercase - Letters that are used for emphasis, as opposed to regular lowercase letters. CAPITAL letters are the same as uppercase letters. The first word in a sentence is usually in uppercase. Some older computers were only capable of displaying uppercase characters. user - A person who uses a BBS. For example, a BBS might claim that it has 500 users, which means that there are 500 different people who have called the BBS. user level - The level of security which a user has. This usual- ly is in the form of word(s), usually progressing from: New User, Registered User, Privileged User, SysOp Level. [See also securi- ty level]. user list - Most BBS programs will allow you to see a list of all the its users. It will show the user's name, and often city and state. This is called the user list. Rarely will it show any phone numbers or more detailed information. user log - A file on a computer running a BBS that lists which users called, what time they called, and sometimes information as to what they did while they were on the BBS. user name - This is the name that a person uses on a computer system. Sometimes an alias is used, but it is more often the user's name or a variation of it. user number - A number that is used by some older BBS programs to keep track of users. On these BBS's, a user would have to remem- ber a specific number as well as his password. Most BBS's now use just use the person's user name instead, which is much easier for a user to remember. userfile - A file that a BBS program has that keeps track of all users of the BBS and their statistics. ---V--- V.21 - The international standard, created by CCITT, that con- trols transmission at 300bps. V.22 - The international standard for transmission at 1200bps, created by CCITT. [See also 212A]. V.22bis - The international standard, created by CCITT, that controls data transmission at 2400bps. V.23 - The CCITT protocol for 1200bps one way, 75bps the other way, transmission. V.29 - A standard for 9600bps half-duplex communications. V.32 - The international standard controlling transmission at 9600bps. It was created by CCITT. It has provisions for fall- back, if the line is too noisy. V.32bis - The international standard for 14,400 bps modems, created by CCITT. V.42 - A standard error control system created by CCITT that is in use on many 9600bps modems and some 2400bps modems. It in- cludes LAPM, as well as MNP 2-4. [See also error control]. V.42bis - A CCITT standard for data compression. It can compress data with about a 3:1 compression ratio, although it can compress up to 4:1 given the right conditions. Any modem with V.42bis also has V.42 error control. [See also data compression]. verify - This is when a SysOp makes sure that a new user is who he or she claims to be. The normal procedure is for the SysOp to call up a new user, just to make sure that the phone number he listed is real. This is a way to make sure that the users are less likely to abuse the system. However, most SysOps do not call new users, since it is time consuming. Some SysOps will look at the information the new user left just to make sure it "look" right (if the new user says his phone number is 555-1212, the SysOp knows it is not real). After verifying the user, the SysOp will usually raise the user's user level. verified user - Any user who has been verified by the SysOp. It is also used to refer to user's who have access better than that of new users. video width - See screen width. videotex - The idea of getting information by computer, over the phone lines, and paying for it. It is the computer version of audiotex (900 numbers, voice mail, having computers call you). virus - Any program which spreads itself secretly. It reproduces within a computer, and also will go to other computers if possi- ble (through file transfers). At a certain point in time, the virus will do something (anything from say "Boo" to something destructive, such as erasing all files on a hard disk drive). They are hidden inside legitimate programs that seem to run normally, but contain the virus. It will usually spread to every program you run. Viruses became widespread because BBS's can inadvertently spread virus all across the country. Whenever you download a program, it might have a virus in it. However, there are several programs available which find many viruses and can destroy them. voice detection - The ability of a modem to detect whether a computer answers the phone, or whether it is a human voice. voice grade - A telephone line that is designed to transfer human voice. This is the way most phone lines are set up. However, the phone company also has data grade lines, which are supposed to make data communications easier. [See also data grade]. voice mail - An addition to some modems. This allows it to answer incoming calls, send recorded (voice) messages to the caller, and let them leave a message. vote - Some BBS's have this feature, which allows the SysOp to find out user's preferences about things ranging from operation of the BBS to political positions. It is similar to a survey in the non-computer world. [Same as poll]. VT100 - A smart terminal, which is emulated by many communica- tions programs. It uses ANSI codes. [See also ANSI]. VT52 - Another smart terminal, which is emulated by some communi- cations programs. ---W--- window - A distinct area of a computer screen that contains information different than the rest of the screen. Sometimes it covers other information (in which case it is temporary), or it is permanent and does not contain other information. [See also SysOp window]. word wrap - A function of editors on BBS's (just like that found in most word processors) which will move a word that won't fit at the very right hand of the screen down to the next line. worm - A program which embeds itself within another program. Either it tries to find a space in which it won't be noticed, or it will just stick itself anywhere within the main program (which will ruin that program). A worm will usually also be destruc- tive. [See also virus]. ---X--- X.25 - This is a packet-switching protocol developed by CCITT. It is used to carry large amounts of data at fast speeds over leased phone lines. X.400 - This is the CCITT standard protocol for a global system for the exchange of electronic mail. X.500 - The CCITT standard for a directory of the users of the X.400 system. [See also X.400]. xfer - Short for Transfer. It usually refers to file transfers. [See also upload, download]. Xmodem - A file transfer protocol developed by Ward Christensen around 1977. It is fairly slow by today's standards, but was the first widespread file transfer protocol. It uses blocks of 128 bytes, and after each block is sent, it sends a 1 byte checksum to check for errors. If an error is encountered, the information will be re-sent. Almost every communications program offers this protocol. [See also protocol]. Xmodem/CRC - The same as Xmodem, but it has a 16-bit CRC instead of the checksum, which makes it more reliable (it catches more errors). [See also protocol]. Xmodem-1K - This is similar to Xmodem/CRC, except it uses blocks of 1024 bytes, rather than 128. It is faster than Xmodem, since it needs to stop less often to check for errors. This is some- times incorrectly called Ymodem. [See also protocol, Xmodem, Ymodem]. Xoff - The CTRL-S character. This is often used to pause infor- mation that is being sent. The information will be continued when an CTRL-Q is received. [See also Xon]. Xon - The CTRL-Q character. This will sometimes continue paused information. [See also Xoff]. ---Y--- yell - See page (verb). Ymodem - A file transfer protocol which can transfer more than one file at a time. It transfers both a file and some informa- tion about the file (including its length, and the name of the file). It is similar to Xmodem/CRC, except that Ymodem can transfer more than one file at a time. It will use CRC-16 if possible, or else it will use a 1 byte checksum. It will use both 1024 byte blocks and 128 byte blocks. [See also protocol]. Ymodem-g - This is Ymodem changed to provide best results with error-correcting modems. Errors can be discovered, since Ymode- m-g uses CRC, but if there are any errors in the transmission, the transmission will be aborted. [See also protocol, streaming]. ---Z--- ZIP - The file extension which refers to archives that were created by the program PKZIP. You need the program PKUNZIP to get the files out of the archive. [See also archive, unarchive, PKZIP, PKUNZIP]. Zmodem - A file transfer protocol which is known for its speed, as well as the ability to transfer information about a file with the file. It has crash recovery and auto-download features, and can use a 32 bit CRC, which makes it almost error-free. [See also protocol]. TRADEMARKS MNP is a trademark of Microcom, Inc. Hayes is a trademark of Hayes Microcomputer Products, Inc. HISTORY Telecommunications Dictionary version 0.99: This was the first version available. It was incomplete, with about 150 words, only covering A-K. It was released in 1989. It was usually in a file called "MODEMDIC". Telecommunications Dictionary version 1.00: This was the first real version. It had somewhere around 430 words defined in it. It was released on August 15, 1991. It was sent out originally as "TDIC100" in a ZIP compressed format. Telecommunications Dictionary version 1.10: This is version 1.10. It has more than 530 words listed. Many words were added, some extra information was added to some old words, and several minor errors were corrected. It is ex- pected to have been released on August 22, 1991 (I've been very busy this past week!). It should be called TDIC110.TXT, or if archived, TDIC110.ZIP (or whatever extension). |