1. The condition that prevails when the numerical aperture of an optical source, such as a laser, light-emitting diode, or optical fiber, exceeds that of the driven element, e.g., optical fiber core.
2. The condition that prevails when the beam diameter of an optical source, such as a laser, light-emitting diode, or optical fiber, exceeds that of the driven element,… (Read More →)

1. In telephony, the generation of potential traffic that exceeds the capacity of a communications system or subsystem.
2. In telephony, a count of telephone call attempts made on groups of busy trunks or access lines.
3. In telephony, traffic handled by overflow equipment.
4. In telephony, traffic that exceeds the capacity of the switching equipment and is therefore lost.… (Read More →)

Any bit other than a user information bit.

See overhead bit.

Digital information transferred across the functional interface between a user and a telecommunications system, or between functional units within a telecommunications system, for the purpose of directing or controlling the transfer of user information or the detection and correction of errors.
Note: Overhead information originated by the user is not considered to be system overhead information. Overhead information generated within… (Read More →)

An arrangement for exchange-carrier-to-interexchange carrier (EC-to-IC) outpulsing that allows seizure of the EC-to-IC trunk and initiation of outpulsing prior to completion of dialing by the calling customer. [T1.104-1988]

1. One of several segments of a computer program that, during execution, occupies the same area of main storage, one segment at a time.
2. To use repeatedly the same areas of internal storage during different stages of the execution of a program.

A larger cell that physically overlays one or more smaller cells. For example, intra-building cells may be encompassed by a larger campus cell. [T1.244-1995]

A load, placed on a device or facility, that is greater than the device or facility is capable of handling, i.e., capable of performing the functions for which it was designed.
Note: Examples of overloads are (a) traffic on a communications system greater than the traffic capacity of the system, (b) for analog inputs, voltage levels above which an analog-to-digital… (Read More →)

Synonym load capacity.