US Robotics COURIER HST User'smanual page 114

COURIER HST
GLOSSARY
Cross-references in the following definitions are printed in boldface.
Analog
Loopback
Analog
Signals
Answer Mode
ARO
ASCII
Asynchronous
Transmission
Auto Answer
Auto Dial
Baud Rate
A modem self-test in which data from the keyboard is sent
to the modem· s transmitter, modulated into analog form,
looped back to the receiver, demodulated into digital form,
and returned to the screen for verification. Tests either the
modem's originate or answer frequency.
Continuous, varying waveforms such as the voice tones
carried over phone lines. Contrast with digital signals.
A state in which the modem transmits at the predefined high
frequency of the communications channel and receives at the
low frequency. The transmit/receive frequencies are the
reverse of the calling modem which is in Originate Mode.
Automatic Repeat Request. A general term for error con-
trol protocols which feature error-detection and automatic
retransmission of defective blocks of data.
~
See HST
and MNP.
American Standard Code for Information Interchange. A
7-bit binary code (0s. ls) used to represerit letters. num-
bers, and special characters such as$. 1
,
and/. Support-
ed by almost every computer and terminal manufacturer.
~ See Appendix B-6 for decimal and hexadecimal code
equivalents.
Data transmission in which the length of time between
transmitted characters may vary. Because the time lapses
between transmitted characters are not uniform, the
receiving modem must be signaled as to when the data
bits of a character begin and when they end. The addition
of Start and Stop bits to each character serves this pur-
pose. Compare Synchronous Transmission.
A feature in modems enabling them to answer incoming
calls over the phone lines without the use of a telephone
receiver.
A feature in modems enabling them to dial phone numbers
over the phone system without the use of a telephone
transmitter.
The number of discrete signal events per second occurring
on a communications channel. Although not technically
accurate. baud rate is commonly used to mean bit rate.
G-1