FAA: Facility Accepted
Facility Accepted (FAA) is one of the message type codes in BICC protocol. It indicates that the FAR is accepted and the use of the facility or operation towards the other side is accepted.

Facilities Based Private Switched Network Services
Facilities Based Private Switched Network Services refers to the services provided by so called Facilities Based Carriers, a long-distance service provider that owns its own physical facilities as opposed to the bulk of the long-distance companies who are resellers.

Facility Loopback
Facility Loopback refers to signal looped back toward the incoming facility. This technique is often used in T1 testing.

Facility-Based Carriers
Facility-based Carriers refers to a local or long-distance service provider that owns its own physical facilities.

Fax: Facsimile Transmission
Fax, also called Facsimile Transmission, is a system of communication or delivery for paper documents or other graphics material in which a special digital image scanner scans the pages of the document, compresses the scanned image using CCITT Group Compression, and transmits the digital signals by wire or radio to a FAX receiver at a remote point.

FBG: Fiber Bragg Grating
Fiber Bragg Grating (FBG) is a short length of optical fiber that filters out a particular wavelength. Periodically spaced zones in the fiber core are altered to have different refractive indexes slightly higher than the core. This structure selectively reflects a very narrow range of wavelengths while transmitting others. Fiber Bragg gratings are used to stabilize the output of a laser and to filter out wavelengths in a WDM system.

FCC: Federal Communications Commission
Federal Communications Commission (FCC) is the regulatory body governing communications technologies in the US. established by the Communications Act of 1934, as amended, and regulates interstate communications (wire, radio, telephone, telegraph and telecommunications) originating in the United States.

FDL: Facility Data Link
Facility Data Link (FDL) is a 4-kbps channel provided by the Extended Superframe (ESF) T1 framing format. The FDL performs outside the payload capacity and allows a service provider to check error statistics on terminating equipment without intrusion.

Feature Boards
Feature Boards are modular system cards that perform specific functionality, for example, DSC cards or modem cards.

FEC: Forward Error Correction
Forward Error Correction (FEC) is a technique for controlling errors in a one-way communication system. FEC sends extra information along with the data, which can be used by the receiver to check and correct the data. Using FEC, a receiver can correct errors incurred in transmission over a communications channel without requiring retransmission of any information by the transmitter, which typically involves a convolution of the transmitted bits and the appending of extra bits by both the receiver and transmitter using a common algorithm.

FER: Frame Erasure/Error Rate
Frame Erasure/Error Rate is a measure of the number of frames of data that contained errors and could not be processed. FER is usually expressed as a percentage or exponent.

FEXT: Far-End Crosstalk
Far-End Crosstalk (FEXT) refers to crosstalk that is measured at the opposite end of the cable from which it is being disturbed.

FG: Feature Groups
Feature Groups (FG), also called access feature groups, are the standard interconnections (paths) between telecommunications carriers (e.g., local exchange and inter-exchange carriers). Currently, there are four common feature categories: FGA, FGB, FGC, FGD.

FGA: Feature Group A
Feature Group A (FGA) is the arrangement that the user has to dial a local telephone number, following by the desired long-distance number.

FGB: Feature Group B
Feature Group B (FGB) is the arrangement that is associated with 950-xxxx calling; the user enters 950 and 4 additional digits, followed by the long-distance number.

FGC: Feature Group C
Feature Group C (FGC) services, replaced by FGD (Feature Group D) now, allows the end user to have the same dialing plan (1 plus the telephone number) to reach any predetermined long distance phone companies of their choice.

FGD: Feature Group D
Feature Group D is a local exchange carrier network service that, among other things, lets public-safety dispatch offices receive a 10-digit data stream, including the full call-back number, alongside wireless 911 calls. FGD is offered as a way by which wireless carriers can meet FCC enhanced 911 rules and dispatch offices can overcome their current bandwidth limits. This access group is associated with equal access arrangements, which allows the end user to have the same dialing plan (1 plus the telephone number) to reach any predetermined long distance phone companies of their choice.

FGD-EANA
Feature Group-D (FGD) of type Exchange Access North American (EANA) is a type signalling protocol that provides certain call services, such as emergency (USA-911) calls. The command calling number outbound is used only for FGD-EANA signalling to generate ANI digits for outgoing calls.

FiOS: Fiber Optic Service
Fiber Optic Service (FiOS) is a data communications service provided by Verizon that uses fiber optic cables to transfer data. FiOS is called a "Fiber to the Premises," or FTTP service, since it brings fiber optic data transmission to residential homes as well as businesses. Since fiber optic technology sends data via pulses of light, it is the fastest method of transferring data.

FISU: Fill-In Signal Unit
Fill-In Signal Unit (FISU) is an SS7 message that is sent in both directions whenever other signal units are not present. FISU provides a CRC checksum for use by both signalling endpoints.

Fixed Access
Fixed access refers to a terminal access to the network in PCS ( personal communications service) that uses wired technology.

FLAG: Fiber Link Around the Globe
Fiber Link Around the Globe (FLAG) refers to an undersea fiber optic cable which connects England, Japan, and many places in between.

F-link: Fully Associated Link
F-link refers to the SS7 fully associated link, which is an SS7 signaling link directly associated with a link carrying traffic. F-link connects two signaling end points (i.e., SSPs and SCPs). F-links are not usually used in networks with STPs. In networks without STPs, F-links directly connect signaling points.

Frame Synchronization
Frame synchronization is the process in the telecommunications transmission system to align the digital channel (time slot) at the receiving end with the corresponding time slot at the transmission end as it occurs.

FRJ: Facility ReJect
Facility ReJect (FRJ) is one of the message type code in BICC (Bearer independent Call Control) protocol (which, in turn, is part of SS7 protocol suite). Facility ReJect message indicates that the request to use the facility (an operation) towards the other side is denied. An example of such operations or facilities could be coin phones.

FSAN Group: Full Service Access Network Group
The Full Service Access Network (FSAN) Group is a forum for the world's leading telecommunications services providers and equipment suppliers to work towards a common goal of truly broadband access networks. The Mission of FSAN is to drive applicable standards, where they already exist, into the services and products in the industry, while simultaneously advanced its own specifications, such as Gigabit rate G-PON and ATM-based B-PON Passive Optical Networking, into the appropriate standards bodies to provide further definition to the Full Service Access Network.

FSN: Forward Sequence Number
Forward Sequence Number (FSN) is part of an SS7 MSU that contains the sequence number of the signal unit.

FTTC: Fiber To The Curb
Fiber-To-The-Curb (FTTC) refers to the installation and use of optical fiber cables directly to the curbs near homes or any business environment as a replacement for "plain old telephone service" (POTS). Think of removing all the telephone lines you see in your neighborhood and replacing them with optical fiber lines. Such wiring would give us extremely high bandwidth and make possible movies-on-demand and online multimedia presentations arriving without noticeable delay.

FTTH: Fiber To The Home
Fiber-To-The-Home (FTTH), also known as Fiber to the Premises (FTTP), refers to a broadband telecommunications system based on fiber-optic cables and associated optical electronics for delivery of multiple advanced services such as the triple play of telephone, broadband Internet and television to homes and businesses.

FTTN: Fiber to the Neighborhood
Fiber-To-The-Neighborhood (FTTN) refers to installing optical fiber from the telephone company central office to all curbs or buildings in a neighborhood.

FTTO: Fiber to The Office
Fiber-To-The-Office (FTTO) refers to installing optical fiber from the telephone company central office to a specific office in a building such as a business or apartment house.

FTTP: Fiber to the Premises
Fiber-To-The-Premises (FTTP), also known as Fiber-To-The-Home (FTTH), refers to a broadband telecommunications system based on fiber-optic cables and associated optical electronics for delivery of multiple advanced services such as the triple play of telephone, broadband Internet and television to homes and businesses.

FTTS: Fiber To The Subdivision
Fiber-To-The-Subdivision (FTTS) refers to the installing optical fiber from the telephone company central office to a subdivision of residential area.

Fully Dedicated Access
Fully Dedicated Access refers to an Internet access service that is fully owned and operated by a company providing and ensuring high reliability, low latency, flexible, robust, and more quality services.

FX: Foreign Exchange
Foreign Exchange (FX), in telecommunication, refers to a service that provides local telephone service from a central office located outside the subscriber's exchange area ( "foreign to" this area). A sample scenario of such service is the following: a user pick up the phone in one area and the dial tone is provided from another area (so called foreign area).