Phone Call Recorder

telephone number

A telephone number is a sequence of decimal digits that uniquely indicates the network termination point. The number contains the information necessary to route the call to this point. Telephone numbers are often assigned to lines that have other devices hooked to them such as faxes, modems, subscribers and network services. Each such endpoint must have a unique number within the public switched telephone network. Most countries use fixed length numbers (for normal lines at least) and therefore the number of endpoints determine the necessary length of the telephone number. It is also possible for each subscriber to have a set of shorter numbers for the endpoints most often used. These "shorthand" numbers are automatically translated to unique telephone numbers before the call can be connected. Some special services have their own short numbers (e.g. 9-1-1, 4-1-1 and 1-1-2). Many systems also allow calls within a local area to be made without dialing the local areas code. Most telephone networks nowadays are interconnected in the international telephone network, where the format of telephone numbers is standardized by ITU-T in the recommendation E.164, which specifies that the entire number should be 15 digits or shorter, and begin with a country prefix. In most countries, this is followed by an area code or city code and the subscriber number, which might consist of the code for a particular telephone switch. ITU-T recommendation E.123 describes how to represent an international telephone number in writing or print, starting with a plus sign ("+") and the country code. To actually call an international number from a fixed line phone (mobiles generally allow the + to be entered directly) the + must be replaced with the international call prefix of the country the call is being made from. The format and allocation of local phone numbers are controlled by each nation's respective government, either directly or by sponsored organizations (such as NANPA overseen by NeuStar Inc.) See Telephone numbering plan. Before a telephone call is connected, the telephone number must be dialed by the calling party or caller. The called party might have equipment that presents caller ID before the call is answered. Businesses used to have a single telephone number for the main switchboard of that business and a switchboard operator would connect the call within the business. If the called party didn't answer, the caller was typically transferred back to the switchboard. With voicemail and more technology, businesses now use Direct Inbound Dialing (DID) (Direct Dialling Inwards (DDI) in the UK) lines so that outside callers can call to a specific person in a business. Often times, the DID number uses a pattern from the called party's telephone internal extension. For example, within the Acme Corporation, a caller may dial 225 to reach Mr. Smith, but an outside caller may dial 448-9225 to reach Mr. Smith (with the last three digits representing Mr. Smith's extension). Some companies restrict the DDI capability to certain parts of the PABX numbering range: Mr Smith on 225 might have it, but Mr Jones on 374 or Mr Brown on 427 would not. If a merger has happened in the past there may even be different exchange codes mapping to different parts of the internal numbering range. Some companies have a sufficient need for internal extensions that the whole numbering range following the exchange code (448 in the example) represents company extensions. A real example of this in the UK is the former Post Office's headquarters in Central London: the PABX was made an end node exchange in the London Director area, with the code 432. The automanual board was given the extension number 1234, so in the days before all-figure numbering outside callers reached the switchboard by dialling HEAdquarters 1234.

List of telephony terms:

3gpp - a-law - abbreviated dialing - adsl - ani - answering machine - apn - automatic ring back - b-channel - baud - bell 202 modem - bit rate - bonding - bri - busy signal - cable modem - call-progress tones - call accounting - call capture - call forwarding - call originator - call park - call pick-up - call transfer - call waiting - call waiting deluxe - called party - caller id - caller id spoofing - calling party - carrier wave - cbr - ccitt - cdma - cdma2000 - cellular repeater - celp - channel - clec - clock rate - codec - collect call - conference - conference call - crc - csd - d-channel - data compression - device driver - dial-up - dial - dial tone - direct-inward-dialing - direct distance dialing - distinctive ring - dnis - dsl - dsp - dtmf - dtr - duplex - echo cancellation - edge - extension - fax - fcc - fdma - fidonet - follow-me - g.711 - g.723.1 - g.723 - g.726 - g.lite - gprs - gps - gsm - h.323 - harmonic - headphones - hscsd - hspda - iad - idsn - internet call waiting - isp - ivr - jack plug - local loop - long distance - microcontroller - mobile phone - modem - modulation - mu-law - music-on-hold - night service - off-hook - on-hook - pabx - pager - payphone - pbx - pcm - pots - prank call - precise tone plan - pstn - pulse dialling - push to talk - ring modulation - ring tone - ringback - ringing signal - rj11 - roaming - serial communications - serial port - signal noise - sim - simplex - sit - sms - softmodem - switchboard operator - tapi - tdma - telecommunications - telemarketing - telephone - telephone call - telephone card - telephone company - telephone exchange - telephone line - telephone number - telephone numbering plan - telephone operator - telephone switchboard - telephony - tts - twisted pair - umts - v.32 - v.32bis - v.34 - v.42bis - vbr - vertical service code - voicemail - voip - vox - wap - wav - wi-fi - wimax - wire