The percentage of time a channel was available for use in a specified period of scheduled availability.
Note 1: Channel reliability is given by where To is the channel total outage time, Ts is the channel total scheduled time, and Ta is the channel total available time.
Note 2: Ts = Ta + To.

A line bridging device that (a) is used to perform loop-back testing, (b) may perform bit stuffing, (c) may also provide a framing and formatting pattern compatible with the network, and (d) is the last signal regeneration point, on the loop side, coming from the central office, before the regenerated signal reaches a multiplexer or data terminal equipment (DTE).

See group.

A time slot that starts at a particular instant in a frame and is allocated to a channel for transmitting data, such as a character or an in-slot signal.

Signaling in which the signals necessary to switch a given circuit are transmitted via the circuit itself or via a signaling channel permanently associated with it.

An application of push technology that allows users to automatically receive specific kinds of content. [Bahorsky]

The use of a single wideband, i.e., high-capacity, facility to create many relatively narrowband, i.e., lower capacity, channels by subdividing the wideband facility.

1. A letter, digit, or other symbol that is used as part of the organization, control, or representation of data.
2. One of the units of an alphabet.

A method of error detection using the preset rules for the formulation of characters.

Software that is capable of selectively removing characters from a data stream, e.g., software that removes communications-control characters so that they are not printed.