Glossary
Glossary-5
3821-A2-GB20-40
January 1999
handshaking
The exchange of predetermined codes and signals (tones) to establish a connection
between two modems.
HDLC
High-level Data Link Control. A communications protocol defined by ISO.
host
A computer attached to a network that shares its information and devices with the rest of
the network.
Hz
A unit of frequency (hertz) that equals one cycle per second.
ISO
International Organization for Standardization.
ITU-T
The Telecommunications Standardization Sector of the International
Telecommunications Union, an advisory committee established by the United Nations to
recommend communications standards and policies. Before March 1993 it was called
CCITT.
JM8
A jack used for leased-line networks. Pins 1 and 2 are the transmit pair and Pins 7 and 8
are the receive pair.
LCD
Liquid Crystal Display. The device that permits text to be displayed on the DCP or
SDCP.
leased line
A private line connection exclusively for the user. No dialing is necessary.
LED
Light-Emitting Diode. A light or status indicator on the DCP or SDCP that glows in
response to the presence of a certain condition (e.g., Alrm).
local analog loopback
Test in which the modem’s transmit VF signal is looped to its receiver.
long space disconnect
A disconnect can occur if the modem receives an extended space from a remote modem;
for example, when a remote modem is commanded to disconnect, it transmits a
continuous space to the modem before disconnecting.
loopback test
Any test that verifies a device’s integrity by connecting the device’s output of one
direction to the device’s input of the other direction, then checking the received signal
for errors.
LSD
Line Signal Detect. A signal between the DTE and modem indicating energy exists on
the transmission circuit.
MNP
This protocol (Microcom Networking Protocol) detects and corrects data errors caused
by telephone line noise and signal distortion. MNP5 includes data compression.
modem
MOdulator/DEModulator. A device that transforms signals from digital to analog form
and vice versa.
modulation
The process of varying some characteristics (usually amplitude, frequency, and/or phase)
of a carrier wave to form data transmissions.
off-hook
The state of a telephone or modem that is being used.
on-hook
The state of a telephone or modem that is not being used.
Summary of Contents for COMSPHERE 3821PLUS
Page 1: ...COMSPHERE 3821PLUS MODEM USER S GUIDE Document No 3821 A2 GB20 40 January 1999 ...
Page 4: ...COMSPHERE 3821Plus Modem C January 1999 3821 A2 GB20 40 Notices ...
Page 8: ...COMSPHERE 3821Plus Modem G January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 12: ...COMSPHERE 3821Plus Modem iv January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 26: ...COMSPHERE 3821Plus Modem 2 8 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 76: ...COMSPHERE 3821Plus Modem 3 50 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 104: ...COMSPHERE 3821Plus Modem 4 28 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 106: ...COMSPHERE 3821Plus Modem 5 2 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 120: ...COMSPHERE 3821Plus Modem 7 12 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 128: ...COMSPHERE 3821Plus Modem B 4 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 134: ...COMSPHERE 3821Plus Modem C 6 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 140: ...COMSPHERE 3821Plus Modem E 4 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 146: ...COMSPHERE 3821Plus Modem F 6 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 148: ...COMSPHERE 3821Plus Modem G 2 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 160: ...COMSPHERE 3821Plus Modem H 12 January 1999 3821 A2 GB20 40 This page intentionally left blank ...
Page 175: ...00282600 ...