   This is a glossary of terms commonly used by telecommunications
   enthusiasts, as well as words specific to offline mail reading and
   Bulletin Board Systems. We hope you find the information useful.

     Adaptive Rate -
         The ability for data communications equipment to react to the 
         changing conditions of the telephone line.  Most modems provide
         this feature to ensure that data is sent and received properly
         even on trouble prone communications lines.

     Analog Loopback Test <local> -
         A test that checks the internal operation of the MODEMS transmit
         and receive circuitry by looping test characters within the 
         modem.

     ARQ -
         Automatic Repeat Request. A general term for error control
         protocols featuring hardware detection and retransmission of
         defective data. This term is used primarily by US Robotics.

     ASCII -
         American Standard Code for Information Exchange.  A 7-bit binary
         code representation of letters, numbers and special characters.
         It is universally supported in computer data transfer.

     Asynchronous -
         Data transmission in which the actual data is preceded by a start
         bit and followed by a stop bit since the time between transmitted
         characters varies.

     Auto Answer -
         The modem feature which enables detection of a ring and answering
         without assistance from a program.

     Baud Rate -
         The number of discrete signal events per second occurring on a
         communications channel. It is often referred to as Bits per
         second (BPS) which is technically inaccurate but widely accepted.

     BBS -
         Bulletin Board System.

     Bit -
         Binary Digit. A single basic computer signal consisting of a
         value of 0 or 1, off or on.

     Buffer -
         A memory area used for temporary storage during input/output
         operations.

     Bulletin Board System -
         A host system, into which callers may dial with their modems to
         read and send electronic mail, upload and download files, and
         chat online with other callers.

     Byte -
         A group of Bits acted upon as a group, which may have a readable
         ASCII value as a letter or number or some other coded meaning to
         the computer. It is commonly used to refer to 8-bit groups. 1
         kilobyte = 1,024 bytes; 64K = 65,536 bytes or characters.

     Carrier -
         A continuous frequency capable of being either modulated or
         impressed with another information-carrying signal. Carriers are
         generated and maintained by modems via the transmission lines of
         the telephone companies.

     Class 1 FAX -
         A FAX protocol in which all handshaking is handled by FAX
         software.

     Class 2 FAX -
         A FAX protocol in which some of the handshaking is handled by FAX
         software, and some is handled by FAXmodem hardware.

     Conference -
         An area of public messages on a Bulletin Board System, usually
         with a particular topic and, often, a conference host or
         moderator to guide the discussion. Also called Folder, SIG (for
         "Special Interest Group") or Echo.

     CCITT -
         A French acronym for the International Telephone and Telegraph
         Consultative Committee. This international organization defines
         the standards for telephone equipment such as the Bell 212A
         standard for 1200 baud, CCITT V.22 for 2400 baud and CCITT V.32
         for 9600 baud.

     CPS -
         Characters Per Second. A transfer rate estimated from the bit
         rate and length of each character. If each character is 8 bits
         long and includes a start and stop bit for Asynchronous
         transmission, each character needs 10 bits to be sent. At 2400
         baud it is transmitted at approximately 240 CPS.

     CRC -
         Cyclical Redundancy Check. An error-detection technique
         consisting of a cyclic algorithm performed on each "block" of
         data at the sending and receiving end of the transmission. As
         each block is received, the CRC value is checked against the CRC
         value sent along with the block. Many protocols including XMODEM-
         CRC and ARQ will request a resend until the block is received
         correctly.

     Download -
         Receiving a file from a Bulletin Board System, using a terminal
         program (for example QModem) and a transfer protocol (for example
         Zmodem).

     DCE -
         Data Communications Equipment. The device that relays the data 
         originated by the DTE.  A modem is an example of a DCE device.

     DTE -
         Data Terminal Equipment. The device that is the originator or
         destination of the data sent by a modem.  A computer is an 
         example of a DTE device.

     DTR -
         Data Terminal Ready. A signal generated by most modems indicating
         a connection between the DTE (computer) and the modem. When DTR
         is "high" the computer is connected.

     Data Compression Protocols -
         Compression of data by the modem allows more information to be
         transferred in a shorter time frame. Protocols for data
         compression include CCITT V.42bis and MNP 5.

     Data Transmission Protocols -
         These are standards for modulation and transmission of data at
         various speeds. The standards are Bell 103 & V.21 for 300bps,
         Bell 212A & V.22 for 1200bps, V.22bis for 2400bps, V.32 for
         9600bps and V.32 bis for 14,400bps. Proprietary protocols are
         also used extensively for higher baud rates.

     Digital loopback test <local or remote> -
         These tests are performed when local and remote modems have a
         data connection.  In a local test, the remote modem sends data to
         your modem, which loops it back to the remote modem.  This 
         lets the remote modem user evaluate his DTE/DCE connection, the
         phone line and your modem.  In the remote test, the opposite 
         occurs, allowing you to verify your serial port <DTE/DCE>, phone
         line and the remote modem.

     Echomail -
         Public Message Conferences on a Bulletin Board System which are
         shared and distributed among other Bulletin Boards as part of an
         Echomail Network.

     Flow Control -
         A mechanism that compensates for differences in the flow of data
         to and output from a modem or computer. Either hardware or
         software can be used for this control to prevent data loss.
         Hardware flow control using the modem makes use of a buffer to
         store data to be sent and data received. Flow control is
         necessary if the Communications port is locked at a higher rate
         than the connection rate.  See RTS/CTS and XON/XOFF

     Error Control Protocols -
         These are various modem-based techniques which check the
         reliability of characters or blocks of data at a hardware level.
         Examples include MNP 2-4, V.42

     Freeware -
         Computer software which may be distributed on Bulletin Board
         Systems, and for which the author requests no license fee or
         registration fee.

     Full Duplex -
         Signal flow in both directions at the same time. It is sometimes
         used to refer to the suppression of online LOCAL ECHO and
         allowing the remote system to provide a REMOTE ECHO.

     Half Duplex -
         Signal flow in both directions, but only one way at a time. It
         is sometimes used to refer to activation of LOCAL ECHO which
         causes a copy of sent data to be displayed on the sending
         display.

     Host System -
         Another name for a Bulletin Board System (BBS)

     LAPM -
         Link Access Procedure for Modems.  An error correction protocol
         specified in CCITT V.42 Recommendation for error correction.

     Local Area Network (LAN) -
         A group of computers joined with cables and software, allowing
         hard disks and other devices to be shared among many users.

     Mail Door -
         A subsection of a Bulletin Board System which creates .QWK mail
         packets.

     MNP -
         Microcom Networking Protocol. A set of hardware error protection
         protocols (MNP levels 1 - 4) and data compression techniques (MNP
         level 5) developed by Microcom, now in the public domain. It
         makes use of CRC and retransmission of defective blocks by
         checking performed within the modem.

     Modem -
         An acronym for MOdulator/DEModulator.  A modem uses standard
         telephone lines to transmit data, and must convert the computer's
         binary language into audio tones (MOdulate) for transmission over
         the telephone lines and then convert the audio tones back to
         binary code (DEModulate) for the receiving computer to process
         the data.

     Netmail -
         Private electronic mail which is transmitted by a user calling
         one Bulletin Board System to another user calling a different
         Bulletin Board System.

     NRAM -
         Nonvolatile Random Access memory. A user-programmable memory chip
         whose data is retained when power to the chip is turned off. NRAM
         is used in many modems to store default settings.

     ON/OFF Hook -
         A descriptive term referring to manually lifting a telephone
         receiver (taking it OFF Hook) and replacing it (going ON Hook).
         OFF Hook produces a busy signal on the phone line.

     Packer -
         A program to compress multiple files into a single file, such as
         ZIP, ARC or LHARC

     Packet -
         A mail packet (with a .QWK extension) from a host system

     Parity -
         An error detection method used in both communications and
         computer memory checking to determine character validity.
         Communications now makes use of more efficient "block" checking
         although parity must still be matched in a communication session
         for transfer to take place correctly. Host communication in the
         BBS environment omits parity checking (no parity).

     Protocol -
         A system of rules and procedures governing communications between
         two devices. File transfer protocols in your communications
         program refer to a set of rules governing how error checking will
         be performed on blocks of data.

     Public Domain -
         Computer software on which no copyright exists (usually by a
         specific statement to that effect by the author), and which may
         be freely used and distributed.

     Remote Echo -
         A copy of the data being received is returned to the sending
         system for display on the screen. See Full/Half duplex.

     RTS/CTS-
         This is hardware flow control, used between the DTE and the DCE.
         When the DCE buffer is nearly full, it will drop the CTS <clear
         to send> signal, halting the data flow from the DTE untill the 
         buffer is nearly empty, when the CTS signal is raised.  RTS 
         <Request to send> and CTS are used together with a time-delay
         option in synchronous applications.

     Shareware -
         Computer software which is distributed on the "Honor System",
         which may be freely copied and distributed, but for which a
         registration fee or payment is required for continued use beyond
         an initial evaluation period.  Copyright may be retained by the
         author.

     Synchronous -
         Transmission in which characters or bits are sent at a fixed
         rate, with the transmitting and receiving devices synchronized
         to each other via precise timing signals.  Control is usually 
         provided by software using special ASCII symbols to frame data.

     SysOp -
         The SYStem OPerator of a Bulletin Board System. The person
         responsible for setting up and maintaining the BBS.

     Thread -
         A group of BBS messages and replies linked and sorted by topic.

     Unpacker -
         A program to uncompress a file from a Packer

     Upload -
         To transfer a file from your computer to another computer, using
         your terminal program (for example Qmodem) and a transfer
         protocol (for example Zmodem)

     V.21 -
         CCITT standard for modem communications at 300bps. Modems made in
         the US follow the Bell 103 standard.

     V.22 -
         CCITT standard for modem communications at 1200bps, compatible
         with the Bell 212A standard used in the US and Canada.

     V.22 bis -
         CCITT standard for modem communications at 2400bps. It includes
         automatic fallback to 1200bps and compatibility with Bell 212A
         and V.22 modems.

     V.23 -
         CCITT standard for modem communications at 1200bps with a 75bps
         back channel. It is used in the United Kingdom.

     V.32 -
         CCITT standard for modem communications at 4800 and 9600bps. It
         includes automatic fallback to 4800 when line quality is poor.

     V.32 bis -
         CCITT standard for modem communications at 14400bps with
         automatic fallback to 12000, 9600, 7200 and 4800bps. As line
         quality improves communications speed can also be increased to
         the next higher rate.

     V.42 -
         CCITT standard for modem communications that defines negotiation
         for LAPM error control. V.42 also includes support for MNP error
         correction protocol levels 1 - 4.

     V.42 bis -
         CCITT extension of V.42 that adds data compression to the V.42
         correction protocols.  Supports up to a 4:1 compression rate, and
         can only be used with LAPM error correction. It is not compabible
         with MNP.
