ASCII - American Standard Code for Information Interchange, which defines the character codes for letters, numbers, punctuation and control characters. Defined in ANSI X3.4-1986.
Baud rate - a measure of the number of times per second a signal in a communications channel varies, or makes a transition between states (states being frequencies, voltage levels, or phase angles). Modems faster than 300 bps usually transmit more than one bit of information for each baud.
Bits per second - measure of the number of data bits transmitted each second in a communications channel.
Break - a signal to the remote system, usually to interrupt a process.
Bulletin Board System (BBS) - a system, often run on a personal computer, that users can call to exchange messages and files.
CCITT - Consultative Committee for International Telephone and Telegraph. See ITU.
Checksum - a method of verifying the integrity of data (not as good as CRC).
CRC - Cyclical Redundancy Check, used to verify the integrity of data.
Data bits - the number of bits used to make up a character.
Flow Control - a mechanism for the receiver of data to signal the sender to suspend transmission when the receiver cannot handle more data. Typically, the receiver has buffers to hold received data and if the buffers get nearly full, it will signal the sender to stop while it catches up on processing the data in the buffer.
Hardware Handshake - a method of flow control using two control lines, usually Request to Send (RTS) and Clear to Send (CTS).
HST - High Speed Technology, the proprietary modulation used by some high speed modems made by US Robotics.
ITU - International Telecommunications Union. They define international standards for modems, among other things. Formerly the CCITT.
Kermit - a file transfer protocol that can work over a connection that only supports seven data bits.
MacBinary - a file format that allows Macintosh files to be stored on non-Macintosh computers. The MacBinary format includes a 128 byte header that contains the full Macintosh file name, the file creator and type codes, and other directory information. When you download a file in MacBinary format, ZTerm will automatically convert it to the normal Macintosh format (unless Transfer Convert is set to Binary Data).
MNP - Microcom Networking Protocol, a suite of compression and error correction protocols designed by Microcom. MNP 5 is a data compression protocol. MNP 2 to 4 are error correction protocols.
Parity - a method of checking the integrity of each transmitted character.
PEP - Packetized Ensemble Protocol, a proprietary modem modulation protocol used by Telebit modems.
Protocol, File Transfer - a set of rules that two computers can use to send a file from one computer to the other. A protocol will usually provide error detection and correction, by resending the portion that was received in error.
Stop Bits - bit(s) used to mark the end of a character during transmission. One stop bit is the most common setting. More than one stop bit was used in days past to slow down transmission for mechanical terminals.
XModem - a file transfer protocol. This one is the most common on personal computer systems.
YModem - a file transfer protocol. YModem is similar to XModem, but uses larger blocks and sends the file name with the file so that multiple files can be sent in a batch.
ZModem - a file transfer protocol. ZModem is one of the most robust and efficient protocols available.
