In digital communications systems, a channel that has a useful capacity of only 56 kb/s (kilobits per second), instead of 64 kb/s.
Note: The restricted channel, currently common in North America, was originally developed to satisfy a ones-density limitation in T1 circuits.

In secure systems, an authorization certificate that indicates the security restrictions on documents and transactions that an entity may authorize. [After X9.45]

Storage in the signaling link control for signal units that have been transmitted but not yet positively acknowledged. [T1.226-1992]

In interactive telecommunications, a service allowing access to and retrieval of stored information, e.g., the information within a database.

Of a satellite orbiting the Earth, an orbit in which the projection of the satellite's position on the (Earth's) equatorial plane revolves in the direction opposite that of the rotation of the Earth.

The ratio, at the junction of a transmission line and a terminating impedance or other discontinuity, of the amplitude of the reflected wave to the amplitude of the incident wave.
Note 1: Return loss is usually expressed in dB.
Note 2: Return loss is a measure of the dissimilarity between impedances in metallic transmission lines and loads, or between refractive… (Read More →)

Signaling which responds to an incoming request for service or change of status.

1. A digital code having two information states, e.g., "0" and "1" or "mark" and "yyspace", in which code the signal returns to a rest state during a portion of the bit period.
2. A code form having two information states termed "zero" and "one" and having a third state or an at-rest condition to which the signal returns during… (Read More →)

Used by standard multicast implementation for loop prevention and to build the multicast distribution tree. If RPF is enabled, network elements will drop multicast packets that are received on an incorrect interface based on the unicast path back towards the source. RPF may be disabled for asymmetric network architectures but other loop prevention techniques must be implemented.

Loop signaling in which battery and ground are reversed on the tip and ring of the loop to give an "off-hook" signal when the call receiver answers.
Note: Reverse-battery signaling may be used either for a short period, or for the duration of a call, to indicate that it is a toll call.