Unintentional signals or noise induced or conducted on a telecommunications or information system signal, power, control, indicator, or other external interface line. [INFOSEC-99]

An amplifier used to enhance the transmission reliability of a usually digital intrafacility metallic transmission line, over extended distances, by driving the input to the transmission line with a higher than normal signal level.
Note: An example of a line driver is an amplifier used to extend the range of an RS-232C digital signal beyond 50 feet (~15 m) while… (Read More →)

A network designed to maintain phantom group balance when one side of the group is equipped with a carrier system.
Note: Since it must balance the phantom group for only voice frequencies, the line filter balance configuration is usually simple compared with the filter that it balances.

See hit.

A network-provided service feature that allows selective denial of call origination to certain lines when excessive demands for service are required of a switching center.

See loop.

A signal used to command the far-end receiver to loopback the received line signal. [T1.107-1988] Synonym [loosely] line loopback signal.

See line loopback.

In a telecommunications link or line facility, interference, from any source, that degrades performance.
Note 1: Line noise is usually measured as a signal-to-noise ratio and as a set parameter used by engineers to determine the operating range of the system.
Note 2: In analog lines, noise is usually measured in dbrnc (dB relative to -90 dBm, with C-message weighting).… (Read More →)

The portion of a device that is connected to external, i.e., outside plant, facilities such as trunks, local loops, and channels.