The symbol designation for frequency is "f."
A 75 ohm coaxial cable connector commonly found on consumer television and video equipment.
Fully Associated Link. A link used to connect two SS7 signaling points when there is a high community of interest between them and it is economical to link them. Also called associated signaling.
Fabric Port. A Fibre Channel term , referring to the port residing on the fabric (switch) side of the link. It attaches to a N Port (Node Port) at the connected device, across a link. See Fibre Channel.
A low cost connector used by the TV industry to connect coaxial cable to equipment. See also F-Type Connector (which is the same thing, except spelled with a dash.)
Fast-Broadcast Control CHannel. A logical channel element of the BCCH signaling and control channel used in digital cellular networks employing TDMA (Time Division Multiple Access), as defined by IS-136. See also BCCH, IS-136 and TDMA.
A 10 MHz PCS carrier serving a Basic Trading Area in the frequency block 1890 - 1895 MHz paired with 1970 - 1975 MHz.
Fixed End System.
These are used to terminate coaxial cable. This connector is mostly used for video applications. It's a male single-conductor connector and screws into the female jack.
Face to Face. When you actually meet someone with whom you have been corresponding electronically , perhaps through a chat room over the Internet. F2F often is quite a surprise, as your "pen pal" may not be anything like he said he was. F2F also can be very dangerous. Never, ever meet someone F2F unless you have a companion with you and you meet in a well-lit public place. Never, ever give the other person your real name , address or telephone number until you have met him F2F and are confident that he is who he says he is. Tell your children to never, never, ever agree to meet someone F2F unless you approve in advance and you are with them at the meeting. This is a very, very dangerous world full of very, very dangerous people who prey on the unsuspecting.
Federal Aviation Commission. If you build a tower of over 200 feet in height you must install FAA approved warning lights on the top. Anything under 200 feet does not need lighting. You can paint your towers all different colors but the most common (for cell phone towers ) is orange and white in 20 foot sections.
Factory that makes ("fabricates") IC chips.
Fabless is a term used to describe a company that designs and sells semiconductor chips but doesn't own a semiconductor manufacturing factory, also called a fabrication plant. Such fabless manufacturer has others make their chips under contract. There are arguments for owning and not owning factory to make semiconductor chips.
A descriptive term referring to the physical structure of a switch or network. Much like a piece of cloth, physical/logical communications channels (threads) are interwoven from port-to-port (end-to-end). Ideally, data are transferred through this switch or network on a seamless basis. In ATM and Fibre Channel, the switching fabric generally is non-blocking , or virtually so, from port-to-port. In the Internet, data works its way through a complex, and even unpredictable, interwoven network of networks comprising transmission facilities, packet switches and multiple carriers . See also Fabric Application Platform.
Multiple Fibre Channel switches interconnected and using Fibre Channel methodology for linking nodes and routing frames in a Fibre Channel network. See Fibre Channel.
What Brocade, a maker of FC (Fibre Channel) switches, calls a technique for running storage software in the network rather than in the host or the FC array. See also Fabric.
A low cost, long wavelength laser used in short and intermediate reach transmitters. Because of a wide spectral width, these devices are not typically used in WDM systems. Lasers are available in either 1310nm or 1550nm wavelength windows . Most Gigabit Ethernet 1000Base-LX modules use 1310nm Fabry-Perot lasers.
See Forced Authorization Code.
I never forget a face, but in your case I'll be glad to make an exception ” Groucho Marx.
Time in front of your boss. Time in front of someone important. Time where you show your face as against working from home or working on a trip. Time where you pitch your ideas to a venture capitalist, as against sending emails or business plans. Time when you show your face, or see someone else's face in the flesh. A fairly stupid term.
A cover that fits around the pushbuttons or rotary dial of a telephone. Hotels and motels put instructions on them. More businesses should also.
An overly pompous way to say "to make easy" or "to make it happen."
A stupid, imprecisely defined word that means anything and everything. To me it sounds like toilets. But it's not. It can mean the equipment and services which make up a telecom system. It can mean offices, factories, and/or building. It can be anywhere you choose to put telecom things. Oops, I nearly said telecom facilities. So "facilities" means practically anything you want it to mean so long as it covers a sufficiently broad variety of "things" which you haven't got a convenient name for. "Facilities" sounds better than "things", especially if you want to sound pompous and erudite.
A PBX feature which allows you, the subscriber, to assign to your users features and privileges like authorization codes, restriction levels and calling privileges.
This feature allows a subscriber to get an audit trail of the referrals produced by the automatic circuit assurance feature of some PBXs. The audit trail will identify the trunk circuit, the time of referral, the nature of the problem and if a test was performed, the outcome of the test.
A telecommunications carrier which owns most of its own facilities (i.e., stuff), such as switching equipment and transmission lines. A non-facilities based carrier is one which leases most of its switching and lines from others. There are probably no 100% facilities based carriers in the world, since even the old government monopoly phone companies leased international lines and all today's competitive carriers lease circuits from each other. There are three benefits to being a mostly-facilities based carrier:
In the long run it tends to be cheaper to own your own plant.
You can roll out new features faster. You don't have to rely on someone else.
You can set your own standards of service and thus achieve better network integrity than if you had to rely on bits and pieces of other peoples' networks.
ILECs (Incumbent Local Exchange Carriers) such as Bell Atlantic, BellSouth, and SBC and IXCs (IntereXchange Carriers) such as AT&T and MCI Worldcom are facilities based carriers under this definition. These IXCs have switching offices, or POPs (Points Of Presence) in all service areas of the United States and provide both originating and terminating service nationwide . Major facilities based carriers sell their services to business and residential users and to other carriers which resell those services.
Non facilities based long distance carriers are known as switchless resellers . To be recognized as a CLEC (Competitive Local Exchange Carrier) by most local regulatory authorities in the United States and to receive reciprocal compensation from the local ILEC, you must, at minimum, own a central office switch; thus you must be a facilities based carrier to some degree. There's probably not one single carrier ” local,long distance or international ” in the entire North America that is 100% facilities based these days. Everyone seems to be renting someone else's lines. The most facilities based would be the ILECs. The least facilities based would be the CLECs (Competitive LECs). They tend to resell local loops from the local ILEC which they terminate in their own switching centers. See also CLEC, ILEC, IXC and POP.
FDL. An Extended SuperFrame (ESF)term. ESF extends the superframe from 12 to 24 consecutive and repetitive frames of information. The framing overhead of 8 Kbps in previous T-1 versions was used exclusively for purposes of synchronization. ESF takes advantage of newer channel banks and multiplexers which can accomplish this process of synchronization using only 2 Kbps of the framing bits, with the framing bit of only every fourth frame being used for this purpose. As a result, 6 Kbps is freed up for other purposes. This allows 2 Kbps to be used for continuous error checking using a CRC-6 (Cyclic Redundancy Check-6), and 4 Kbps to be used for a FDL which supports the communication of various network information in the form of in-service monitoring and diagnostics. ESF, through the FDL, supports non- intrusive signaling and control, thereby offering the user "clear channel" communications of a full 64 Kbps per channel, rather than the 56 Kbps offered through older versions as a result of "bit robbing." FDL implementations can vary, and the 4Kbps data bandwidth can be allocated among different functions, such as managing line side and equipment side operations. For example, ADC just introduced a new HDSL service to compete with T-1. ADC allocates 2 Kbps of the FDL channel for managing the HDSL interface and 2K bps for remotely managing attached channel banks and data terminals. As you can see, FDL has great potential for reducing the cost of onsite provisioning and maintenance.See also ESF and T-1.
Also called Outsourcing, facilities management is having someone else run your computers or your telecommunications system. The concept is that you're a great bank and you should concentrate on being in the banking business. Your outside facilities manager should concentrate on running your computers or telecom systems. He can do it cheaper, allegedly. Ross Perot's Electronic Data Systems (EDS) probably started facilities management. Mr. Perot incorporated EDS on June 27, 1962. At that time he was a leading IBM salesman . See also Outsourcing.
Which types of calls a PBX user is entitled to make.
A telephone industry term for a phone or data line. Sometimes (but rarely) used to describe equipment. See Facilities for a far better description.
Compensation for the use of direct trunk transport, based on relative usage. Relative usage should reflect the percentage of use for all carriers involved. Traffic studies to determine relative usage are typically done only on local terminating minutes of use during the busy hour .
The electrically interconnected system of conductors and conductive elements that provides multiple current paths to the earth electrode subsystem. The facility grounding system consists of the earth electrode subsystem, the lightning protection subsystem, the signal reference subsystem, and the fault protection subsystem. Faulty grounding causes more phone and computer problems than any other single factor.
An order to a phone company to rearrange things.
How they abbreviate the word facsimile in Bermuda.
Facilities Access Control Systems. A collection of dozens of interrelated computer applications developed by the former AT&T Bell Operating Companies which manage the local loops connecting customers to the Public Switched Telephone Network.
FAX. Equipment which allows hard copy (written, typed or drawn material) to be sent through the switched telephone system and printed out elsewhere. Think of a fax machine as essentially two machines ” one for transmitting and one for receiving. The sending fax machines typically consists of a scanner for converting material to be faxed into digital bits, a digital signal processor (a single chip specialized microprocessor) for reducing those bits (encoding white space into a formula and not an endless series of bits representing white), and a modem for converting the bits into an analog signal for transmission over analog dial-up phone lines. The receiving fax consists of a modem and a printer which converts the incoming bits into black and white images on paper. More modern and more expensive machines also have memory ” such that if the machine runs out of paper, it will still continue to receive incoming faxes, storing those faxes into memory until someone fills the machine with paper and it prints the faxes out.
There are six internationally accepted specifications for facsimile equipment. Group 1, Group 2, Group 3, Group 3 Enhanced, Super GE and Group 4. Only 1, 2, 3 and 3 Enhanced will work on "normal" analog dial-up phone lines. Group 4 is designed for digital lines running at 56/64 Kbps, e.g. ISDN lines. Among the analog line fax machines, Group 2 is faster than Group 1. Group 3 is faster than Group 2, etc. Virtually all machines sold today are Group 3, though an increasing percentage are Group 3 enhanced, which has speeded up Group 3's transmission speed from 9,600 bps to 14,400 bps and improved its error correction. Group 3 faxes send an 8-1/2 x 11 inch page over a normal phone line in about 20 seconds. How much time it actually takes depends on how much stuff is actually on the paper. Unlike older machines, Group 3 machines are " intelligent ." They only transmit the information that's on the paper. They do not transmit white space, as earlier machines did. Super G3 is a new "standard" for higher speed fax machines, which contain a 33.6 Kbps V.34 modem, V.8 handshaking and the new ITU-T T.85 JBIG image compression. On most phone lines such a machine should get close to double the speed of the highest speed Group 3 fax machines ” 14.4 Kbps. But, the JBIG image compression will speed faxing of gray scale images by at as much as five to six times. In short, these machines will send faxes much faster ” if they send to a Super G3 machine at the other end. Super G3 is compatible with and can communicate with older fax machines, Group 1, 2, 3 and 3 Enhanced.
When a fax machine calls a phone line, it emits a standard ITU-T-defined, "CNG tone" (calling tone) ” 1100 Hz tone every three seconds. When the receiving fax machine hears this tone, it knows it's an incoming fax call and it can automatically connect. With this tone it is possible to insert a "fax switch," which would "listen" for an incoming fax call and switch it to a fax machine if it heard the CNG tones or to something else ” like a phone or answering machine ” if it didn't. It is not possible to do this with a modem. A calling modem does not issue any tones whatsoever. A modem works backwards ” when the receiving modem answers the phone, it emits a tone.
Typically, a Group 3 machine can speak to a Group 2 and a Group 1 machine. A Group 2 can speak to a Group 1. Speaking down means slowing down. Fax machines are dropping in price. "Personal" fax machines are emerging. Most fax machines today at Group 3 or Group 3 enhanced.
Group 4 machines are 100% digital, transmit at 64,000 bps and directly attach to the B (bearer channel) of a digital ISDN line. They will transmit a sheet of 8 1/2 x 11 paper in under six seconds. The author of this dictionary has seen a working Group 4 fax machine. It's mighty impressive.
The latest ITU standards include T.37 and T.38. T.37 is a new ITU standard for transferring of facsimile messages via store and forward over packet-switched IP networks ” the Internet, corporate Intranets, etc. T.38 is a new ITU-T standard for sending real-time facsimile messages over packet-switched IP networks ” the Internet, corporate Intranets, etc.
Some warnings on fax machines:
All analog Group 3 and enhanced Group 3 fax machines pose a security risk. Anyone can attach a normal audio cassette recorder to a phone line, record the incoming or outgoing fax "tones" of an analog fax machine. By playing back to another fax machine at a later time, you'll get a perfect reproduction of the fax. There are now fax encryption devices which make the fax transmission unintelligible to any machine other than the one it's intended for ” i.e. the one that has a similar un-encryption device.
Some plain paper fax machines present a different security risk. Some (not all) use a carbon ribbon the width of their paper. As a result, if you want to read what came in, you simply read the carbon ribbon, which you open like a scroll, which the cleaning lady finds in the trash. These machines are increasingly less common, as plain paper fax machines acquire laser printing engines.
Most fax machines record all the digits dialed into them which were used to set up a fax call. If a fax machine is sitting behind a PBX (as many are these days) it will capture all the confidential authorization codes of all the company's employees . To get those codes all you need do is ask the machine to print out a report. There is no easy solution to this problem as at the time of writing this dictionary, except that some fax makers have told me they intend to obscure these numbers on their reports, at some stage. Some may, by the time you read this.
Slimy paper fades. How long it takes to fade depends on a bunch of factors ” from what's sitting on top of the fax, to the temperature in the room, to whether it's exposed to sunlight, etc. Recommendation: If you want to retain a slimy fax, make a photo copy of it the moment you get it and throw out the original.
Poor quality slimy fax paper can abrade the fax machine's drum and cause a costly repair. Don't buy cheap slimy fax paper.
Plain paper fax machines cost more to buy, but less to run. You can buy a second tray for some plain paper fax machines which will hold 8 1/2" wide x 14" long paper, which is useful for receiving faxes from outside the US where they use longer paper. This way you save a sheet of paper.
It makes sense to have banks of fax machines attached to phones which roll over ” also called "hunt." It makes absolutely no sense to have multiple fax machines on separate phone lines that don't hunt, i.e. one for everybody in the office. Two fax machines in rotary can receive and transmit more than twice the number of faxes that two machines on separate, non-hunting phone lines can send and receive. "Personal" fax machines should be out. Banks of fax machines should be in. Egos, though, usually prevail over logic.
The paper feed mechanism on plain fax machines has a tendency to jam. Slimy paper fax machines don't jam because their paper typically comes in rolls. And roll paper doesn't jam. The feed mechanism is much simpler.
Plain paper fax machines, like laser printers (which many are) use supplies, like toner, which run out. When the supplies run out, such machines usually accept incoming faxes into memory ” until that runs out. Then they just ring and ring and ring. Which means that incoming faxes don't get through and don't roll over to the next machine. There is no simple solution since the FCC (Federal Communications Commission) has ruled that fax machines must not return a busy signal to the central office if it runs out of supplies or paper. We have a separate machine that automatically busies out a line if it failed to answer on the fifth ring. But so far, the device is not commercially available. I don't know the answer to this problem except to make sure your fax machine is always stuffed with supplies. Especially check every Friday night. A final note: If your plain paper fax machine is missing supplies, but stuffed with incoming messages in memory, don't turn it off, since you'll lose the messages. Simply replace the supplies and pray your messages will emerge.
Some slimy fax paper rolls are coated on the inside of the paper. Others are coated on the outside. When you put one in a fax machine and images don't appear on the paper, then turn the roll over and feed it from underneath. In short, ignore what the instruction book says.
Fax modem switches only work when they're called automatically by a fax machine ” not by a person using a fax machine manually and is waiting the sound of the distant fax prior to pushing the "Send" button. Make sure you warn your senders. It's remarkable how many people manually dial their faxes and thus penetrate fax modem switches.
Think about putting your fax machine on "fine." You'll transmit better quality faxes and may only cost yourself 10% more in transmission time. But that savings depends on the quality of the fax machine at the other end. If it's an older machine, it may cost you as much as double the transmission time. Here are the numbers: Standard is 203 x 98 dpi. Fine is 203 x 196 dpi. "Fine" faxes obviously look much better.
Printed circuit cards which slide into slots of PCs and allow you to transmit and receive faxes work well ” when transmitting faxes. They work far less well when receiving faxes ” largely because of the difficulty of reading faxes. Faxes conform to one type of digital encoding and PC screens conform to another. Moreover a PC screen is landscape (i.e. horizontal), while a fax message is portrait (i.e. vertical). Viewing vertical images on horizontal screens is difficult. Here is a comparison of how fax machines and how personal computer screens encode their images. Obviously, the more digits or pixels, the clearer the end picture. Notice that the encodings are completely dissimilar:
Standard, Group III 203 x 98
Fine, Group III 203 x 196
Superfine, Group III 203 x 391
Standard, Group IV 400 x 400
PC SCREEN ENCODING
CGA 320 x 200
Enhanced CGA 640 x 400
EGA 640 x 350
Hercules 720 x 348
VGA 640 x 480
Super VGA 800 x 600
8514/A (also called XGA) 1,024 x 768
See also 1966, 1978, 1980, demodulation, facsimile converter, Facsimile Recorder, Facsimile Signal Level, Facsimile Switch, Fax, Fax At Work, Fax Back, Fax Board, Fax Data Modem, Fax Demodulation, Fax Mailbox, Fax Modem, Fax Publishing, Fax Server, Fax Switch, Faxbios, Group 1, 2, 3, 3 BIS and 4, Phase A thru E, T.37 and T.38 and Windows Telephony.
A facsimile device that changes the type of modulation from frequency shift to amplitude and vice versa.
Denotes alphabetic, numeric, or graphic information which can be transmitted and received by facsimile machines.
That part of the facsimile receiver that performs the final conversion of the facsimile picture signal to an image of the original subject copy on the record medium.
The facsimile signal power or voltage measured at any point in a facsimile system. It is used to establish the operating levels in a facsimile system, and may be expressed in decibels with respect to some standard value such as 1 milliwatt.
A new breed of "black box." Its purpose is to avoid having to lease a separate phone line for your facsimile machine, for your phone and for your modem. You buy this box, connect it to an incoming line, connect it to your fax machine, your phone and, possibly, your modem. When a call comes in, the fax switch answers the call, listens if the call coming in is from a fax machine (it can hear the fax machine's CNG calling tone) and switches the call to the fax machine, or switches the call to your modem if a computer is calling. It knows if a computer is calling because the calling computer will, when it hears the fax switch answer, send out some ASCII characters ” e.g. 22. (You must put those numbers in your modem dialing stream.) And it knows if a person is calling because it hears neither a CNG tone from a fax machine nor touchtones from the dialing stream of a modem.
The above are the basics of how fax switches work. There are variations on this theme. Some fax switches work automatically. Some work by the incoming caller punching in digits. Some allow you to switch from fax machine to modem to phone and back again. And some fax switches will answer and connect to three modems and one fax or other combinations. The major problem with fax switches is that they typically send a DC ringing tone to whatever device they're trying to connect you (the incoming caller with). Sometimes some devices ” for example, high-speed 9600 baud and higher modems ” have difficulties responding to low power, DC ringing signals. And they just sit there not answering. Better to buy one that sends standard telephone company AC ringing signals. In short, before you buy a fax/modem/phone switch, test it on your favorite 9,600 or 14,400 bps modem. The more expensive switches tend to work better.
Factoids are paragraph size pieces of "Gee Whiz" information. They were originally made famous in the newspaper, USA Today.
An RFID definition. Some read-only have to have their identification number written into the silicon microchip at the time the chip is made. The process of writing the number into the chip is called factory programming.
A term used in the secondary telecom equipment business. Equipment that has been returned to the factory and the factory has replaced plastic, repaired, upgraded boards , or otherwise reconditioned.
A reduction in a received signal which is caused by reflecting, refraction or absorption . See also Fading.
The depth of fade, expressed in dB, that a microwave receiver can tolerate while still maintaining acceptable circuit quality.
The reduction in signal intensity of one or all of the components of a radio signal.
A video term. A progressive deterioration of picture quality due to increasing losses in an electromagnetic (radio) propagation path . The term "fading" may be illustrated by the following sequence:
Noise appears on the porches and tip of the sync pulses .
Noise appears in the picture.
Loss of picture due to loss of synchronization which in turn is caused by distortion of the sync pulse by noise.
Force Administration Data System. A system which takes basic statistics on telephone traffic and gives hints as to how many operators should be employed to answer the incoming calls and when they should be present.
A specially designed system that continues working after a failure of some component or piece of the system. There are precious few, genuinely fail safe systems. To be genuinely fail safe, a system needs to be completed duplicated . It is prohibitively expensive for most commercial users to duplicate every part of their system. But you can duplicate selectively and bring yourself closer to "fail safe." The extent of the duplications you choose (and thus the cost of your telephone equipment and transmission system) depends on how important it is that your system function as close to 100% as possible. The idea is to identify those things most likely to break and to duplicate them. Power is clearly the first area to focus on. These days, the words "FAIL SAFE" are increasingly being replaced with "FAULT TOLERANT." Given the number of times your local, friendly airline has told you that its "computer is down," you can understand the reason for the wording change.
When one individual computer fails, another automatically takes over its request load. The transition is invisible to the user. Failover involves switching off the failed redundant component and switching on the backup unit. A disk subsystem is running in failover mode when it switches to a hot spare or begins to use the backup disk in a mirrored pair.
I never thought it necessary to define this obvious word. But then I'm reading an IPO prospectus for a new switching company and bingo, it defines failure as, "A termination of the ability of an item to perform a required function. A failure is caused by the persistence of a defect." In case you're wondering, the IPO succeeded.
Area in which a failure occurred in a Token Ring, defined by the information contained in a beacon. When a station detects a serious problem with the network (such as a cable break), it sends a beacon frame that includes the station reporting the failure, its nearest active upstream neighbor (NAUN), and everything in between. Beaconing in turn initiates a process called autoreconfiguration. See NAUN.
The number of failures of a device per unit of time.
A term used in the secondary telecom equipment business. One step up from "as is" condition. Equipment may have been tested ; i.e., product is in working order but looks semi- awful .
An ATM term. As related to Generic Flow Control (GFC), fairness is defined as meeting all the agreed quality of service (QOS) requirements, by controlling the order of service for all active connections.
Per PacBell lore, this is the tinkle tinkle sound you get when you use some calling cards. Per the lore, the sound was recorded from Tinkerbell in the musical Peter Pan and is the intro to the calling card recording, i.e. they play Fairydust then the talent comes on and says "thank you for using xxxxxx long distance, please enter your card number etc."
Faith is believing in something in spite of the fact that you have no hard evidence that it exists.
A subdirectory on the file server of a local area network that functions as a root directory, where you can safely assign rights to users. Fake roots only work with NetWare shells included with NetWare v2.2 and above. If you use older versions of the workstation shell, you will not be able to create fake roots.
Also called turn-off time. The length of time required for a pulse to decrease from 90 to 10 percent of its maximum amplitude. Also, the length of time required for a component to achieve this result.
An early virus which made the characters on a screen fall to the bottom.
Mechanism used by ATM networks when rigorous path selection does not generate an acceptable path. The fallback mechanism attempts to determine a path by selectively relaxing certain attributes, such as delay, in order to find a path that meets some minimal set of desired attributes.
A modem speed that is lower than its normal (that is, maximum) speed of operation. May be used when communicating with a slower, compatible modem, or to help transmission over a line that is too noisy for full speed operation.
When used in the context of biometrics this term refers to the case where an authentication system erroneously denies access to an authorized person. See the next definition.
When used in the context of biometrics this term refers to the case where an authentication system erroneously grants access to an unauthorized entity. See the previous definition.
False ringing is a recording of a telephone ringing signal (two seconds on, four seconds off, which is played while a call is transferred or while a switching device listens for modem for facsimile CNG (calling) tones.
In telecom signaling, DTMF tones are created using specific combinations of frequencies to prevent the possibility of "falsing." Falsing is the condition where a DTMF detector incorrectly believes a DTMF is present when in fact it is actually a combination of voice, noise and/or music.
The art of spacing your children the proper distance apart to keep you on the edge of financial disaster.
An aerial consisting of a number of wires radiating upwards from a common terminal to points on a supporting wire.
Equipment that breaks down DS1 or DS3 service to the size demanded by the customer. On a DS3 line it breaks out the 28 DS1 channels. On a DS1 line it breaks them into 24 DS0 channels.
Someone who's overly enthusiastic about something in which you have zero interest.
Formats And Protocols. The set of rules that specifies the format, timing, sequencing and/or error checking for communication between clients and servers.
Either Frequently Asked Question, or a list of frequently asked questions and their answers. Many Internet USENET news groups, and some non-USENET mailing lists, maintain FAQ lists (FAQs) so that participants won't spend lots of time answering the same set of questions.
Crosstalk which travels along a circuit in the same direction as the signals in the circuit. The terminals of the disturbed channel at which the far-end crosstalk is present and the energized terminals of the disturbing channel are usually remote from each other.
Synonym for Far-Field Radiation Pattern.
In voice recognition, far talk is an arrangement where a microphone is more than four inches from the speaker's mouth. The opposite is CLOSE TALK, where the microphone is closer than four inches.
The practical unit of capacity. A capacitor which retains a charge of one coulomb with a potential difference of one volt. See Faraday and Faraday Cage.
As a Faraday shield: refers to the protection a material or container provides to electronic devices to keep them from exposure to electrostatic fields. Named after M. Faraday, the English physicist .
A structure designed to isolate a sensitive electronic system or device from outside interference, usually constructed of metal screens. Named for 19th century inventor Michael Faraday, whose name also gave us the FARAD, the unit of measuring capacitance .
Also known as the Magneto- Optic Effect. A phenomenon that causes some materials to rotate the polarization of light signals in the presence of a magnetic field that is parallel to the direction of the propagation of the light signal. Also called magneto-optic effect.
Farland is an alliance of European telecom carriers operators whose common network unites the infrastructures of its members ' national networks to one pan-European fiber optic network. Farland launched its operations in March 1999. Farland is owned by BT (British Telecom).
Picture a hall full of computers (PC servers and/or mainframes), lined one after another. Now you have the concept of a farm.
Frame Alignment Signal or Frame Alignment Sequence. See Frame Alignment Signal.
Toward the end of the 15th century, men's shoes had a square tip, like a duck's beak, a fashion launched by Charles VIII of France to hide the fact that one of his feet had six toes.
F-BCCH. A logical channel element of the BCCH signaling and control channel used in digital cellular networks employing TDMA (Time Division Multiple Access), as defined by IS-136. See also BCCH, IS-136 and TDMA.
A busy signal which sounds at twice the normal rate (120 interruptions per minute vs. 60 a minute). A "fast busy" signal indicates all trunks are busy.
A call center term. A caller who hangs up immediately when they hear a delay announcement.
100BaseT. Ethernet at 100 Mbps, a tenfold improvement over the original Ethernet speed of 10 Mbps. Fast Ethernet is in the form of an Ethernet hub with an internal bus that runs at 100 Mbps. The interface to the hub is through a port which generally is selectable (i.e., programmable) to run at either 10 Mbps or 100 Mbps, depending on the requirement of the attached device. Connection between the hub and the attached workstation or other device is over data-grade UTP ( Unshielded Twisted Pair) in the form of Cat (Category) 5, at a minimum, and over distances of up to 100 meters , at a maximum. The attached device connects to the UTP connection via a 10/100 Mbps NIC (Network Interface Card). 100BaseT hubs interconnect over fiber optic facilities, which can support 100 Mbps over relatively long distances with no loss of performance. Fast Ethernet is no longer all that fast- Gigabit Ethernet switches were standardized in 1998. See also 10BaseT, 100BaseT, Cat 5, Ethernet, Gigabit Ethernet, NIC and UTP.
A group of vendors that participated in writing the 100Base-X technical hub and wiring specifications, which would allow fast Ethernet (100 megabits a second) to run over Category 5, data-grade unshielded twisted pair wiring.
FFT. An ISDN term referring to the fact that file transfers can be accomplished "fast." Reason #1: Two B channels at 64 Kbps each are available to be bonded to provide as much as 128 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 acknowledgments. This is possible due to the excellent level of error performance inherent in digital services. The end result is FFT.
FFT. 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 approximation of the possibly infinite series described by the purely mathematical application of the Fourier Transform. See Fourier's Theorem.