Facility. A single functional entity in a network.

Facsimile (fax). A means of transmitting documents using telecommunications circuits with a device that scans the document and uses coded signals to transmit the document content to another destination.

Facsimile server. A server that allows a number of users on a computer network to use the same fax machine.

Fading. The reduction in intensity of a signal or part of a signal.

Fax modem. A modem with fax transmission and reception capabilities.

FCC (Federal Communications Commission). A U.S. government agency primarily responsible for the allocation of radio spectrum for communications services in the United States.

FDD (Frequency Division Duplexing). In a FDD system simultaneous transmission and reception of radio signal is possible. This allows the mobile phone user to talk and listen at the time. The mode of communication is facilitated by having a frequency channel with two separate operating frequencies, one for transmission and the other for reception.

FDMA (Frequency Division Multiple Access). The process of dividing bandwidth into multiple frequencies which can be shared out among base transceiver stations (BTS)within the network.

FEC (Forward Error Correction): An error correction technique that does not require retransmission of errored data. Extra redundant bits must be added to the information signal in FEC.

Features. Inherent benefits offered by a product.

FH-SS (Frequency Hopping-Spread Spectrum). FH-SS is a form of spread spectrum modulation in which the narrowband information-bearing signal is spread over a wide range of frequency by hopping its carrier frequency in a pseudo-random pattern.

FIFO (First In/First Out) . A call queueing technique where the call that enters the queue first is dealt with first.

Filter. A device that can distinguish a desired signal from interference and supresses any interference.

Flag. A unique bit pattern used in TDMA that identifies the beginning or the end of a frame.

Flat rate service. A service charged at a fixed price regardless of usage, for example, line rental.

Flexible line ringing. The use of different ringing tones for different lines within an organization.

Forward channel. A one-way communications path that carries signals from the calling party to the called party.

Footprint. An area of the earth that a satellite signal is able to reach with a usable signal.

Frame. A vehicle for the transmission of data over a link. It can be described as a collection of bits, including the address, data, and control information, that is switched and transmitted over a link. The size and composition of the frame varies according to the protocol used. The terms packet and frame are often used interchangeably.

FRAMES: Future RAdio wideband Multiple AccEss System. FRAMES was a project undertaken under the ACTS programme to develop the UMTS air interface.

Frequency. The speed of an electromagnetic transmission. Frequency can be defined as the number of cycles per second of an electromagnetic transmission usually measured in hertz. Generally, high frequency transmissions can carry more information at greater speeds than low frequency transmissions.

Frequency group. In cell planning, a frequency group is a set of frequencies allocated to each cell, and is determined by the network operator. In a cluster, different sets of frequencies are allocated to neighboring cells.

Frequency Re-Use. In a PLMN, the ability of two base transceiver stations to use the same group of frequencies for transmitting and receiving, provided they are a sufficient distance apart.

FSS (Fixed Satellite Services). ). A satellite service that involves point-to-point communication, e.g., for TV program exchange. There is no direct reception by customers.

FSS (Fixed Satellite Services). A satellite service involving point-to-point, non-customer connections.

Full duplex transmission. A communications circuit that can transmit and receive information simultaneously.