Telephone number

phone numbertelephone numbersphone numbers
A telephone number is a sequence of digits assigned to a fixed-line telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN) or other public and private networks. A telephone number serves as an address for switching telephone calls using a system of destination code routing. Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange.

North American Numbering Plan

Area codeArea codesArea code(s)
The NANP divides the territories of its members into numbering plan areas (NPAs) which are encoded numerically with a three-digit telephone number prefix, commonly called the area code. Each telephone is assigned a seven-digit telephone number unique only within its respective plan area. The telephone number consists of a three-digit central office code and a four-digit station number. The combination of an area code and the telephone number serves as a destination routing address in the public switched telephone network (PSTN). For international call routing, the NANP has been assigned the international calling code 1 by the International Telecommunications Union (ITU).

Telephone call

callphone callphone calls
Preceding, during, and after a traditional telephone call is placed, certain tones signify the progress and status of the telephone call: Cell phones generally do not use dial tones, because the technology used to transmit the dialed number is different from a landline. Unsolicited telephone calls are a modern nuisance. Common kinds of unwanted calls include prank calls, telemarketing calls, and obscene phone calls. Caller ID provides some protection against unwanted calls, but can still be turned off by the calling party.

Telephone exchange

exchangescentral officeexchange
Instead, the RT is connected digitally to equipment in the telephone switch. This reduces the total amount of equipment required. Switches are used in both local central offices and in long distance centers. There are two major types in the Public switched telephone network (PSTN), the Class 4 telephone switches designed for toll or switch-to-switch connections, and the Class 5 telephone switches or subscriber switches, which manage connections from subscriber telephones. Since the 1990s, hybrid Class 4/5 switching systems that serve both functions have become common. Another element of the telephone network is time and timing.

Voice over IP

VoIPvoice over Internet Protocolvoice-over-IP
Voice over Internet Protocol (also voice over IP, VoIP or IP telephony) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services (voice, fax, SMS, voice-messaging) over the public Internet, rather than via the public switched telephone network (PSTN).

Signalling System No. 7

SS7SS7 networkCCS7
Signaling System No. 7 (SS7) is a set of telephony signaling protocols developed in 1975, which is used to set up and tear down most of the world's public switched telephone network (PSTN) telephone calls. It also performs number translation, local number portability, prepaid billing, Short Message Service (SMS), and other mass market services. In North America it is often referred to as CCSS7, abbreviated for Common Channel Signaling System 7. In the United Kingdom, it is called C7 (CCITT number 7), number 7 and CCIS7 (Common Channel Interoffice Signaling 7). In Germany, it is often called ZZK-7 (Zentraler ZeichengabeKanal Nummer 7).

Telephone

phonetelephonesLocal Telephone Service
This gave rise to landline telephone service in which each telephone is connected by a pair of dedicated wires to a local central office switching system, which developed into fully automated systems starting in the early 1900s, and eventually into a worldwide public switched telephone network. For greater mobility, various radio systems were developed for transmission between mobile stations on ships and automobiles in the mid-20th century. Hand-held mobile phones were introduced for personal service starting in 1973. In later decades their analog cellular system evolved into digital networks with greater capability and lower cost.

VoIP phone

IP PhoneIP phonesEthernet-based phone
A VoIP phone or IP phone uses voice over IP technologies for placing and transmitting telephone calls over an IP network, such as the Internet, instead of the traditional public switched telephone network (PSTN). Digital IP-based telephone service uses control protocols such as the Session Initiation Protocol (SIP), Skinny Client Control Protocol (SCCP) or various other proprietary protocols. VoIP phones can be simple software-based softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone. Traditional PSTN phones are used as VoIP phones with analog telephone adapters (ATA).

9-1-1

911911 call9-1-1 call
With regard to mobile phones, the rules require carriers to connect 9-1-1 calls from any mobile phone, regardless of whether that phone is currently active. Similar rules for inactive telephones apply in Canada. When a cellular phone is deactivated, the phone number is often recycled to a new user, or to a new phone for the same user. The deactivated cell phone will still complete a 9-1-1 call (if it has battery power) but the 9-1-1 dispatcher will see a specialized number indicating the cell phone has been deactivated. It is usually represented with an area code of (911)-xxx-xxxx. If the call is disconnected, the 9-1-1 dispatcher will not be able to connect to the original caller.

Caller ID

caller line identificationCLIcaller-identification technology
In the typical telephony environment, a PBX connects to the local service provider through Primary Rate Interface (PRI) trunks. Generally, although not absolutely, the service provider simply passes whatever calling line ID appears on those PRI access trunks transparently across the Public Switched Telephone Network (PSTN). This opens up the opportunity for the PBX administrator to program whatever number they choose in their external phone number fields. Some IP phone services (ITSPs, or Internet Telephony Service Providers) support PSTN gateway installations throughout the world. These gateways egress calls to the local calling area, thus avoiding long distance toll charges.

Directory assistance

directory enquiries118 500Telephone Directory assistance
Example: The caller is looking for a listing in Los Angeles, CA (area code 213) and dials 213-555-1212. In this case Verizon bills the call. 4) 00 and ask for the international directory assistance operator. AT&T provides International Directory Assistance calls. See www.consumer.att.com/global/english/country_codes.html for additional information and country and city codes. 555 (telephone number). Telephone directory.

Wireless home phone

A wireless home phone service is a service that allows a regular wired telephone to connect to a cellular network, as if it were a mobile phone. It is an example of a wireless last mile connection to the public switched telephone network, also known as a wireless local loop. A small device, about the size of a home wireless router, contains the necessary electronics which allow plain old telephone service to be provided to one or two telephone jacks on the back of the unit, as well as having a small radio antenna and a transceiver for the wireless side of the connection. LED indicator lights on the front typically show signal strength and voicemail messages waiting.

Toll-free telephone number

toll-freetoll-free number800 number
Countries around the world use various dialing prefixes to denote toll-free services in their telephone networks. Toll-free numbers in the North American Numbering Plan (NANP) are commonly called "800 numbers" after the original area code which was used to dial them. They include the area code 800 (since January 1, 1966), 888 (since March 1, 1996), 877 (since April 4, 1998), 866 (since July 29, 2000), 855 (since October 9, 2010), 844 (since December 7, 2013), and 833 (since April 22, 2017). Area codes reserved for future expansion include 822, 880 through 887, and 889. The original Wide Area Telephone Service is obsolete.

Overlay plan

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It was originally established as an area code specifically for cell phones and pagers in New York City, but soon after, the FCC said area codes going forth could not be service-specific, but they allowed 917 to remain as such. However, 917 is being used for landlines in New York City on a limited basis. List of area code overlays. Interexchange carrier. Telephone exchange. Telephone numbering plan. Exhaust date.

Google Voice

Grand Central
Caller ID spoofing. Comparison of VoIP software. Level 3 Communications. Public switched telephone network. PrivatePhone. Traffic pumping.

Index of telephone-related articles

Plain old telephone service (POTS). Private branch exchange. Public switched telephone network. Satellite phone. Sidetone. Telecommunications. Telephone. Telephone call. Telephone directory. Telephone exchange. Telephone line. Telephone newspaper. Telephone number. Telephone switchboard. Telephone tapping. Telephony. Thomas Edison. Timeline of the telephone. Tip and ring (Wiring terminology). Toll-free telephone number.

Landline

fixed linefixed-lineland line
The term landline is also used to describe a connection between two or more points that consists of a dedicated physical cable, as opposed to an always-available private link that is actually implemented as a circuit in a wired switched system (usually the public switched telephone network). So-called leased lines are invariably of the latter type; the implications of a land line in this context are security and survivability. For example, a military headquarters might be linked to front-line units "by landline" to ensure that communication remains possible even if the conventional telephone network is damaged or destroyed. Another example of this is in airports.

Fictitious telephone number

fictional telephone numbersPlaceholder telephone numbersfictional numbers
Per the ACMA web page – Fictitious numbers for radio, books, film & TV, version October 21, 2009: In Hungary, telephone numbers are in the format 06 + area code + subscriber number, where the area code is a single digit 1 for Budapest, the capital, followed by a seven digit subscriber number, and two digits followed by either seven (for cell phone numbers) or six digits (others). for other areas, cell phone numbers or non-geographic numbers like toll-free or premium-rate numbers. Two digit area codes which consist of digits between 2 and 9 are geographic areas, while area codes ending with a 0 or a 1 denote other services.

Mobile radio telephone

0Gmanual mobile telephone systemmobile radio telephony
The B-Netz launched 1972 in West Germany as the country's second public commercial mobile phone network (but the first one that did not require human operators to connect calls). List of mobile phone generations. 1G. 2G. 3G. 4G. 5G. Mobile rig. Mobile Telephone Service - (A pre-cellular VHF radio system that linked to thep PSTN). Radiotelephone - (A communications device for transmission of speech over radio). Satellite telephone. Mobile Phone History. Mobile Phone Generations. Storno.co.uk.

Videotelephony

videoconferencingvideo conferencingvideo chat
The widest deployment of video telephony now occurs in mobile phones. Nearly all mobile phones supporting UMTS networks can work as videophones using their internal cameras, and are able to make video calls wirelessly to other UMTS users in the same country or internationally. As of the second quarter of 2007, there are over 131 million UMTS users (and hence potential videophone users), on 134 networks in 59 countries. Mobile phones can also use broadband wireless Internet, whether through the cell phone network or over a local wifi connection, along with software-based videophone apps to make calls to any video-capable Internet user, whether mobile or fixed.

Emergency telephone number

emergency callemergency numberemergency calls
In many countries the public switched telephone network has a single emergency telephone number (sometimes known as the universal emergency telephone number or the emergency services number) that allows a caller to contact local emergency services for assistance. The emergency number differs from country to country; it is typically a three-digit number so that it can be easily remembered and dialed quickly. Some countries have a different emergency number for each of the different emergency services; these often differ only by the last digit. See List of emergency telephone numbers. The emergency telephone number is a special case in the country's telephone number plan.

Robocall

robocallingrobocallsIndiana
Most products use methods similar to those used to mitigate SPIT (spam over Internet telephony) and can be broadly categorised by the primary method used. However, due to the complexity of the problem, no single method is sufficiently reliable. Solutions are available as both hardware and software products. Mobile apps are especially prevalent as they use techniques which do not require the modification of infrastructure. Many products are limited to use only on a single medium, such as traditional copper landlines, or mobile phone contracts from a specific mobile phone operator.

Vertical service code

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Public switched telephone network. Short code. Signalling System 7.

Nortel

Nortel NetworksNorthern ElectricNorthern Telecom
It served both general businesses and communications carriers (landline telephone, mobile phone, and cable TV carriers). Technologies included telephonic (voice) equipment, fiber optics, local wireless, and multimedia. Past products included: In 2016 the Canadian Broadcasting Corporation, reported that lawyers and accountants received $2.5 billion from Nortel's estate In September 1991, Julian Assange of WikiLeaks was discovered in the act of hacking into the Melbourne master terminal of Nortel. In 2004, it was discovered that crackers (malicious hackers) gained almost complete access to Nortel's systems.

Telephone company

telephone companiestelcotelcos
Bell Telephone Company, forerunner of AT&T in the U.S. Internet telephony service provider. Competitive local exchange carrier (in Canada and the U.S.). Communications service provider. History of the telephone. Incumbent local exchange carrier (of the Bell System). List of telephone operating companies. List of mobile network operators. Mobile network operator. Plain old telephone service (POTS). Public switched telephone network. Telecommunications Industry Association (for the development of U.S. telecom standards). Regional Bell Operating Company (in the U.S.). Service provider. Telecommunications service provider. The Phone Company, free, non-commercial email-to-fax service.