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COMSPHERE 3900 Series Modems
NIM
Network Interface Module. The interface provided for the public switched telephone network
(PSTN). There are two NIMs per carrier.
NMS
Network Management System. A computer system used for monitoring and controlling network
devices.
nonlinear distortion
VF line distortion which is usually associated with pulse-code modulation (PCM) compandor
noise on the phone line.
off-hook
The state of a telephone or modem that is connected to the network.
offline
The state of a modem that is not connected to another modem.
on-hook
The state of a telephone or modem that is not connected to the network.
online
The state of a modem that is connected to and communicating with another modem.
Originate mode
The modem is in a state where it is ready to transmit a call. In a dial network, it is the modem
that makes the call. In a leased-line network, it is one of two sides of the network that is selected
to be the originating modem.
parity
A way of checking data accuracy by counting the number of bits that have a value of one.
PBX
Private Branch Exchange. Telephone switching equipment dedicated to one customer. A PBX
connects private telephones to each other and to the public dial network.
permissive interface
A dial modem operating mode characterized by a fixed output power level of –9 dBm. It is one of
two possible modes of operation for modems connected to dial lines (see programmable
interface).
phase jitter
A rapid or repeated shifting of the relative phase of a signal resulting in unwanted distortion.
physical address
The diagnostic address of a control device derived from its location in the carrier; its carrier and
slot number.
point-to-point line
A line or circuit connecting two stations.
poll list
A list containing the network management addresses of downstream modems.
POTS
Plain Old Telephone Service. Standard telephone service over the PSTN, with an analog
bandwidth of less than 4 KHz.
power-up self-test
A test that checks most hardware components when power is applied to the device or a reset is
initiated.
protocol
A set of rules that determines the behavior of devices in achieving and maintaining
communication.
PSTN
Public Switched Telephone Network. A network shared among many users who can use
telephones to establish connections between two points. Also known as dial network.
Quick Configuration
An informative display screen available from the modem's Top-Level display. It provides such
information as network position (control or tributary), network management address, DTE mode
display
(Asynchronous or Synchronous), Line mode (Leased Answer, Leased Originate, or Dial), and the
modulation scheme used by the modem.
register
A part of the device's memory that holds stored values.
remote
Files, devices, and users not attached to your local DTE.
remote loopback
A test that sends a signal to the remote modem to test the local modem, the remote modem, and
the circuit between them.
result code
An asynchronous message (in either numbers or words) that the device sends to the DTE after
executing or trying to execute a command.
Glossary-6
September 1998
3910-A2-GN32-40
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