ZyXEL Communications Omni 288S - Manual (Page 130)

Glossary
D-1
Analog: Not digital. Analog quantities may have any value.
Analog loopback test: Testing method in which the modem's analog output signal is
connected to the analog input.
Answer: In a connection between two modems, one modem works as the recipient (in
answer mode) and the second modem as the initiator (originate mode).
AppleTalk: A simple network to connect several computers directly with each other.
AppleTalk is also the protocol according to which connected computers exchange data. In
Apple Macintosh computers, this network protocol is part of the system software.
ARQ: Automatic Retransmission reQuest - Standardized method in error control
protocols.
ASCII: American Standard Code for Information Interchange. This code assigns a 7-bit
numerical value to characters, digits and control characters. An ASCII character is a 7-bit
character with a decimal value ranging from 0 to 127.
Asynchronous: Data transfer method in which a character's data bits are framed by
additional bits (start bit, parity bit and stop bit). There are variable idle times between
characters.
AT command: The commands used with an intelligent modem. Every command line is
started with the AT prefix (ATtention). To send an AT command to a modem, you must
have communications software running.
Auto-answer: Modem's ability to automatically answer a call after a set number of rings.
Baud: Unit of modem transmission speed. Characters pre second. Named after Baudot, a
French engineer who developed the Baudot code - the precursor of today's ASCII code.
BBS: Bulletin Board System, or Mailbox. Computer software which can send and receive
messages and files via a modem automatically and which can interact with a remote user.
This program usually runs unattended on a computer specifically reserved for this task.
bis: Old French word for two.
Bit: Smallest unit of information. A bit can have one of two states: ON (1; set) and OFF
(0; not set). By combining a number of bits, a computer can code any information. A
byte consists of 8 bits. Therefore a byte can have any one of 28 (256) states.
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 measurement. 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.