ZyXEL Elite 2864 User Guide - Page 238

Bit rate: Count of data bits transmitted per time unit. The framing bits needed for asynchronous transfer are also counted in the calculation of the bit rate. In general, the bit rate is ten times the character rate. bps: Unit of the bit rate; bits per second. Carrier: The carrier is a modulated tone and is used by the modem to transfer the data. CCITT: Comité Consultatif International Téléphonique et Télégraphique; former name for the ITU-TSS (ITU-T), the international standard making organization for telecommunications. CD: See DCD. CEPT: Commission Européenne Postale et Telephonique. This organization regulates the data exhange between the European postal services and participates in the drafting of some standards. Class 2: A standard for fax transfers using a fax modem. Currently several drafts exist which are incompatible with each other. ZyXEL modems support the draft PN-2388 of Aug. 20th 1990, and the final 2.0 standard. CNG: Call negotiation tone. A calling fax machine sends this tone before connecting to quickly establish a fax connection. A data modem may also have a data calling tone. Command mode: In command mode, a modem accepts commands from the local DTE. Data transfer is suspended while the modem is in command mode. Compatibility: If components are compatible, they work with each other. COM port: Another name for the serial port on a PC. Compression: See data compression. CRC: Cyclic redundancy check; an error checking protocol. CTS/RTS: Control signal lines on an RS-232C serial interface. These lines are needed to use hardware flow control. Cursor: A special marker on a display. It marks the position where input from the ZyXEL LCD model's front panel will be shown on the display. Data bit: In asynchronous transfers, a character is composed of data bits (the actual information) and framing bits (start bit, stop bit/s, parity bit). The framing bits are needed to recognize whether a character has been successfully transmitted and where a new charater starts. Data compression: Recoding of information. The same information is represented by less data bits. ZyXEL modems use MNP4 and V.42 compression schemes. Glossary-2