A silly abbreviation for First Come First
Facility Circuit ID.
Abbreviation for Function. This button enables your cellular phone or fax machine or other telecom device to access special features, like switching from one cellular phone company to another. See also Dual NAM.
Fully programmable classes of service that control
See Fiber Control Office Terminal.
Frame Check Sequence. Any mathematical formula which derives a numeric value based on the bit pattern of a transmitted block of information and uses that value at the receiving end to determine the existence of any transmission errors. In bit-oriented protocols, a frame check sequence is typically a 16-bit field that contains transmission error checking information, usually appended to the end of the frame. See Frame Check Error and Frame Check Sequence.
Federation of Communications Services.
A Frame Check Sequence error occurs when a packet is involved in a collision or is corrupted by noise.
Fibre Channel Systems Initiative
See Floor Distributor.
Food and Drug Administration. Organization responsible for laser safety.
Forward Digital Control CHannel. A digital cellular term defined by IS-136, which addresses cellular standards for networks
Floppy Disk Drive. A Hard Disk Drive is a HDD.
Frequency Division Duplex. A method used to achieve full duplex communications in wireless systems. The principle is that forward and reverse directions each use a separate and equally large frequency
Fiber Distributed Data Interface. FDDI is an ANSI standard (X3T12) for a 100-Mbps fiber
A faster FDDI. Said to
DAC Dual Attachment Concentrator
DAS Dual Attachment Station
ESF Extended Service Frames
LER Link Error Rate
LLC Logical Link Control
MAC Media Access Control
MIC Media Interface Connector
NIF Neighborhood Information Frame
PDU Protocol Data Unit
PHY Physical Protocol
PMD Physical Media Department
PMF Parameter Management Frames
RAF Resource Allocation Frames
RDF Request Denied Frames
SAC Single Attachment Concentrator
SAS Single Attachment Station
SDU Service Data Unit
SIF Station Information Frames
SMT Station Management
SRF Status Report Frame
THT Token Holding Timer
TRT Token Rotation Timer
TTRT Target Token Rotation Timer
TVX Valid Transmission Timer
UNA Upstream Neighbor Address
Fiber Distributed Data Interface-II is a recently standardized enhancement to FDDI. It still runs at 100 million bits per second on fiber or on twisted copper pairs, but in addition to transporting conventional packet data like other LANs, FDDI-II allows portions of the 100 Mbps bandwidth to carry low delay, constant bit rate, isochronous data like 64 Kbps telephone channels. This means the same LAN that carries computer packet data can carry live voice or live video calls. Some additional terms used with FDDI-II are: I-MAC which stands for Isochronous Media Access Control; P-MAC which stands for Packet Media Access Control; and WBC which stands for Wide Band Channel. See FDDI, FDDI Terms, Isochronous and Isoethernet.
Facilities Data Link. A T-1 term,
In the original Bell System scheme, the repair station in the CO queries the CSU at the customer site, which responds with error statistics for the last 24 hours (in 15-min
The more modern ANSI method has the CSU broadcast the error statistics for the last three seconds, every second (with overlap). Automatic monitoring equipment in the CO can tell when the line is going bad. Both systems can co-exist and operate on the same link, but that's
Frequency Division Multiplexing. A technique in which the available transmission bandwidth of a circuit is divided by frequency into narrower bands, each used for a separate voice or data transmission channel. This means you can carry many conversations on one circuit. The conversations are separated by "guard channels." At one point, FDM was the most used method of multiplexing long haul conversations when they were transmitted in analog microwave signals. No more. Fiber optic transmission (today's preferred method) uses TDM ” Time Division Multiplexing.
Frequency Division Multiple Access. One of several technologies used to separate multiple transmissions over a finite frequency allocation. FDMA refers to the method of allocating a discrete amount of frequency bandwidth to each user to permit many simultaneous conversations. In cellular telephony, for example, each caller occupies approximately 25 kHz of frequency spectrum. The cellular telephone frequency band, allocated from 824 MHz to 849 MHz and 869 MHz, consists of 416 total channels, or frequency slots, available for conversations. Within each cell, approximately 48 channels are available for mobile users. Different channels are allocated for neighboring cell sites, allowing for re-use of frequencies with a minimum of interference. This technique of assigning individual frequency slots, and re-using these frequency slots throughout the system, is known as FDMA. See CDMA, TDMA.
Fiber Optic Distribution Panel.
Frequency Division Switching. Seldom used for voice switching. Primarily used for radio and TV broadcasting.
See Full Duplex.
Extended Framing ("F sub E"). An old
Another designation for AT&T's ESF (Extended SuperFrame).
An imaging term. An effect in which the edges of a pasted selection or paint tool fade progressively at the edges for a seamless blend with the background.
The term came from the American Indian tradition of obtaining feathers for headdresses. Birds were captured, some feathers plucked, and the birds were released. Each feather represented an act of bravery. The fashion of decorating hats with feathers declined in the twentieth century because too many birds were being slaughtered for their feathers.
A pound of feathers weighs more than a pound of gold. Feathers are weighed by "avoirdupois" weight measure, which has 16 ounces to a pound, while gold is weighed in "troy" measure, which only has 12 ounces to a
A code in the form *XX or XX and currently used by end users for control of and access to custom calling services (such as activation and
When a vendor can't tell you in simple words what his equipment does, he says his equipment (or software) is "feature-rich."
A feature is one of the many
Modular system cards that perform specific functionality - video or modem cards, for example.
Think of a feature button on a telephone as a collection of numbers stored in a bin. When you hit the button, the bin quickly disgorges all the numbers one after another. Feature buttons are fast ways of doing things. You have a feature button labelled "Conference." Hit the button, set up a conference call. Without a feature button, you'd probably have to hit the switch hook and some
This is a number that is used to activate a particular feature on a phone system.
Feature/function testing is designed to assure that everything a system is supposed to do is done correctly, e.g. calls are switched to the correct destination, messages are left and deleted, billing records collected accurately, and so on. Feature/function testing is the most detailed portion of the test process. The people who perform functional testing must be extremely detail oriented and have the discipline to test every feature to their written functional requirement. No function of the system should be overlooked. Definition
FGA, FGB, FGC, FGD, are four separate switching arrangements available from local exchange carrier (LEC) end central offices to interex- change (long distance)
Offers access to the local exchange carrier's network through a subscriber-type line connection rather than a trunk. It is a continuation of the ENFIA arrangement used in the early days of OCCs, until equal access using an access tandem central office is available. Remember, without equal access the IX carrier had to require its customers to dial a local number to reach their long distance facilities, then dial an identification number, then dial long distance numbers of the called party desired. This service handicap, compared to AT&T's
Is similar to FGA, but provides a higher quality trunk line connection from end CO to the IX carrier's facilities, instead of the subscriber-type line. The IX customer can originate a call from
Is the traditional toll service arrangement offered by LECs to AT&T prior to breakup of the Bell System. Quality is superior, and the service includes automatic number identification of the calling party, answerback, and disconnection supervision, and the subscribers can use either a dial or touchtone pad. This FGC service is offered only to AT&T without a discount.
FGD. The class of service associated with equal access arrangements. All facilities based IXCs (IntereXchange Carriers) and
Same as FEATURE BUTTONS. A key is to a telephone man what a switch is to an electrical man.
A generic name for a telephone that has extra features (often speed dial buttons) designed to simplify and speed making and receiving phone calls.
A PBX to PBX signaling exchange which trigger additional PBX services after a connection have been established, e.g. to display calling party name and number, call back when busy, call forwarding, executive override etc. Feature transparency is implemented by all major PBX
Feature/function testing is designed to assure that everything a system is supposed to do is done correctly, e.g. calls are switched to the correct destination, messages are left and deleted, billing records collected accurately, and so on. Feature/function testing is the most detailed portion of the test process. The people who perform functional testing must be extremely detail oriented and have the discipline to test every feature to their written functional requirement. No function of the system should be overlooked. Definition courtesy Steve Gladstone, from his book "Testing Computer Telephony Systems."
Far End Block Error. A maintenance signal transmitted in the PHY (Physical) overhead, indicating that a bit error(s) has been detected at the PHY layer at the far end of the link. The PHY is the Physical Layer (Layer 1) of the OSI Reference Model, and refers to the transmission facility, such as T-3 or SONET link. A block is a data block, such as a T-3 frame or an OC-1 SONET frame. The "far end" is the end of the physical circuit farthest from the edge of the network, i.e., the premises end. Errors are
On the Roman holiday Lupercal (February 14) goats were sacrificed and the blood was smeared on two specially
Forward Error Correction. A technique used by a receiver for correcting errors incurred in transmission over a communications channel without requiring retransmission of any information by the transmitter. Typically involves a convolution of the transmitter using a common algorithm and embedding sufficient redundant information in the data block to allow the receiver to correct. While this technique is processor-
Forwarding Equivalence Class. A MPLS (Multiprotocol Label Switching) term. See MPLS.
Forward Explicit Congestion Notification. A Frame Relay term. This bit contained within the Address Field notifies the receiving device that the network is experiencing congestion. Thereby, the target device is advised that frames may be delayed, discarded, or damaged in transit. It is the responsibility of the target device to adjust to that condition. In conjunction with BECN, devices in both the forward and backward directions are advised. See BECN.
Field Emission Display. A new way of making TV and computer screen displays. FED screens are flat and
Fire Emitting Diode. Diodes not installed properly can become SEDs (Smoke Emitting Diodes), which then can become FEDs. See also Diode.
A system of standards numbered FED-STD-1001 to 1008 which set modulation specifications for data transmission.
FAA. The federal regulatory agency responsible for air safety. Establishes antenna tower marking requirements.
FCC. The federal organization in Washington D.C. set up by the Communications Act of 1934. It has the authority to regulate all interstate (but not
Stripped of all the
It sets the prices for interstate phone, data and video service.
It determines who can or cannot get into the business of providing telecommunications service or equipment in the United States.
It determines the electrical and physical standards for telecommunications equipment and services. The FCC's powers, although strong, are tempered (limited) by the Federal Courts. Anyone who disagrees with FCC rulings can
How is the FCC organized? Most items
The Common Carrier
The Mass Media Bureau regulates television and radio broadcasts.
The Wireless Bureau oversees wireless services such as private radio, cellular telephone, personal communications service (PCS), and
The Cable Services Bureau regulates cable television and related services.
The International Bureau regulates international and satellite communications.
The Compliance & Information Bureau investigates violations and answers questions.
The Office of Engineering & Technology
The Office of Plans and Policy develops and analyzes policy proposals.
The Office of the General Counsel reviews legal issues and defends FCC actions in court.
The Office of the Secretary oversees the filing of documents in FCC
The Office of Public Affairs distributes information to the public and the media.
The Office of the Managing Director
The Office of Legislative and Intergovernmental Affairs coordinates FCC activities with other branches of government.
The Office of the Inspector General reviews FCC activities.
The Office of Communications Business Opportunities provides assistance to small businesses in the communications industry.
The Office of Administrative Law Judges adjudicates disputes.
The Office of Workplace Diversity ensures equal employment opportunities within the FCC.
FIPS. The identifier attached to standards developed to support the U.S. government computer standardization program. The FIPS effort is carried out by the U.S. Department of Commerce, Springfield, VA. See the next definition.
The Fed. The federal government agency that sets interest rates and
FTSC. A U.S. government agency established in 1973 to promote standardization of communications and network interfaces. FTSC standards are identified by the designator FED-STD. The FTSC's address is General Services Administration, Specification Service Administration, Bldg 197, Washington Navy Yard, Washington DC 20407.
FTS. The private network used primarily by the civilian agencies of the federal government to call other government locations and to place calls to phones connected to the PSTN (Public Switched Telephone Network). FTS is a TTTN (Tandem Tie Trunk Network). A TTTN is a large, complex, private switched network which generally involves dedicated COs (Central Offices), as well as dedicated transmission facilities. See also AUTOVON and TTTN.
An organization with representatives from the FCC and the state public service commissions which
This is an interesting story about the commercialization of the Internet. The Federated States of Micronesia is a developing island nation in the Western Pacific Ocean, with a population of about 100,000. The country has little need for its Internet TLD (Top Level Domain) of .fm. So, the government of FMS announced on October 8, 1998 a joint agreement with BRS Media to begin registering and marketing the .fm TLD to the broadcasting industry. A number of FM radio
A television signal source.
The return of part of an output signal back to the input side of the device. Think of the high-pitched squeal you hear when someone
The inevitable result when your baby doesn't appreciate the strained
A group of wires, usually 25-pair or
A process by which output or behavior of a machine or system is used to change its operation in order to constantly reduce the difference between the output and a target value. A simple example is a
The cable running between bridges, line extenders and taps.
A network of loop cable extending from a wire center into a segment of the area served by the wire center.
A segment of a feeder route that is uniform throughout its length with respect to facility requirements and facilities in place.
Holes punched in paper or papertape which allow the paper or paper tape to be driven by sprocket wheels.
The feedhorn is the focal point of a dish antenna. The feedhorn collects the signals reflected by the dish. The feedhorn is the device used for receiving or radiating microwave signals to or from a
Software designed to get demand for a product or a new market segment started. Feedware is typically a less-full featured piece of software than the software you're really trying to sell. Feedware typically costs very little. It may even be free. See also Seedware.
First Ended, First Out. A rule for dealing with things in a queue. For example, higher priority messages will be sent before lower priority messages.
Front end interface.
Also called a C Connector or 25-pair female connector. The male version is called a P connector.
One-millionth of a billionth of a second. Femtoseconds are used in laser transmission and in other measures of very small happenings. It's 10 to the minus 15. There are as many femtoseconds in one second as there are seconds in thirty million
Front End Processor. The "traffic cop" of the mainframe data communications world. Typically sits in front of a mainframe computer and is designed to handle the telecommunications burden, so the mainframe computer can concentrate on handling the processing
Fluorinated Ethylene Propylene. Also known by the trade name Teflon, a registered trademark of Dupont, and NeoFlon, a registered trademark of Daikin. FEP is the insulation of choice for high performance cable and wire systems installed in return air plenums. As FEP is really slick, it makes the wire really easy to pull through
Frame Error Rate. A computation based on the number of frames received with errors compared to frames received without errors. See also Frame Error Rate.
Far-End Receive Failure. A yellow alarm. A message from a remote network element that is having trouble receiving a signal.
Far-End Remote Failure. An alarm indicating a failure at the far end of an ATM network, identifying the specific circuit in a failure condition.
A central office in German. In Europe, they call a central office a "public exchange," or just plain "exchange." They look at you kinda
A coating used on tape comprising a layer of ferric oxide particles and a layer of chromium dioxide particles and combining the attributes of both.
A coating used on tape comprised of red iron oxide, the original material used for magnetic recording tapes.
A type of ceramic material having magnetic properties and consisting of a crystalline structure of ferric oxide and one or more metallic oxides, such as those of nickel or zinc. See Barium Ferrite, Hard Ferrite and Soft Ferrite.
A special transformer which puts out
A component of a fiber optic connection that holds a fiber in place and aids in its alignment.
Field Effect Transistor. Very thin and small
Far-End CrossTalk. A type of crosstalk which occurs when signals on one twisted pair are
A smaller number. The word "fewer" is always
Form Feed. A printer function used to skip to the top of the next page or form.
Fast Fiber Data Interface. A proprietary 100 megabit per second local area network that uses fiber optic, coax,
Fiber Follow On LAN. Emerging LAN technology.
Fast File Transfer. An ISDN term referring to the fact that file transfers can be accomplished "fast." Reason #1: Two B channels at 64 Kbps each and a D channel at up to 16 Kbps are available to be bonded to provide as much as 144 Kbps. Reason #2: Data transfer is accomplished in an "optimistic" streaming mode, rather than a "pessimistic" packet mode. Therefore, there is no delay associated with acknowledgements. This is possible due to the
Fast Fourier Transform. A signal processing term for a common computer implementation of Fourier Transforms. The FFT, as a practical implementation, will always result in a finite series of sine and cosine waves as an extremely close