Paradyne COMSPHERE 3920PLUS Series, Technical Reference Manual

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COMSPHERE 392xPlus Modems
Glossary-6 October 1998 3920-A2-GH30-40
function key Any one of three keys on the DCP that allows you to select or increment an LCD entry.
Function keys are labeled F1, F2, and F3.
half-duplex Two-way data communications allowed in only one direction at a time.
handshaking The exchange of predetermined codes and signals (tones) to establish a connection
between two modems.
HDLC High-Level Data Link Control. A communication protocol defined by the International
Standards Organization (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.
idle A state in which the modem’s operating parameters can be modified or commands can be
issued to the modem using either AT commands or the DCP.
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.
kHz Kilohertz. A unit of frequency equal to 1,000 cycles per second.
keypad A set of seven keys surrounding the DCP’s LCD. These keys are used to select
configuration options and to maneuver through the DCP menu.
LCD Liquid Crystal Display. A thin sandwich of two sealed glass plates containing liquid
crystal material. When voltage is applied, the amount of light able to pass through the
glass plates is altered so that messages may be “written” on the display.
leased line A private telephone line connection exclusively for the user. No dialing is necessary.
LED Light Emitting Diode. A light or status indicator on the DCP that glows in response to
the presence of a certain condition (e.g., an alarm).
local analog loopback 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 local modem before disconnecting.
loopback test Any test that verifies a device’s integrity by connecting the device’s output to the
device’s input, then checking the received signal for errors.
menu tree The structure containing the menu hierarchy starting at a Top-Level menu and extending
down to various modem functions.
mixed inbound rates In a multipoint network, several different data rates from tributary modems’ transmitters
communicating with one control modem.