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U-90E Data/Fax Modem
Appendix A
Glossary
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).
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
AT
command: The commands used with an intelligent modem. Every command line is started with the
AT
prefix (ATtention). To send an
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.
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.
Glossary
A
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