Digital subscriber line

DSLdigital subscriber linexDSL
A naked DSL (also known as standalone or dry loop DSL) is a way of providing DSL services without a PSTN (analogue telephony) service. It is useful when the customer does not need the traditional telephony voice service because voice service is received either on top of the DSL services (usually VoIP) or through another network (mobile telephony). It is also commonly called a UNE (for unbundled network element) in the United States; in Australia it is known as a ULL (unconditioned local loop); in Belgium it is known as "raw copper" and in the UK it is known as Single Order GEA (SoGEA).

Number pooling

number pooling
Widescale introduction of new area codes created confusion as consumers were often unaware which were domestic-rate calls and which were premium calls to Caribbean or foreign numbers within the NANP. The new area codes brought an initial flood of split plans which changed millions of existing numbers. Businesses in the newly created area codes (such as area code 520 in Arizona) found many clients attempting to call them were instead repeatedly reaching a wrong number due to incompatible or misconfigured switching equipment at call origin which could not handle the new codes.

History of videotelephony

We were certain that such a device would make cell phone communications much more convenient and enjoyable." Saburi also stated that their R&D section had "nourished [the idea] for several years before" they received project approval from their top management which had encourage such forward-thinking research, because they "also believed that such a product would improve Kyocera's brand image." Their research showed that a "cell phone with a camera and color display provided a completely new value for users, It could be used as a phone, a camera and a photo album".

Trillium Digital Systems

TrilliumTrillium Digital Systems, Inc.Product History
Trillium software products were used in communications and networking products designed for the PDN, PSTN, Internet, enterprise networks and home networks. Trillium's evolution and development, paralleled the evolution and development of the communications industry. In 1988 there were less than 1/2 million Internet users, about 4 million cell phone users and no broadband (DSL, cable) users. The industry went through significant transitions from the mid-1980s through the early 2000s, as described in the market history section. By 2008 there were over 1.4 billion Internet users, almost 3.3 billion mobile phone users and over 1 billion broadband users.

Emergency telephone number

emergency telephone numberemergency callemergency number
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.

VoIP spam

SPIT (SPam over Internet Telephony)SPIT
Robocalls can be delivered automatically using telephony software, such as Asterisk. RFC 5039 contains some basic methods for the mitigation of telephony spam over SIP: * White lists and black lists * Consent-based communications * Reputation systems * Address obfuscation and limited-use addresses * Turing tests, captchas, computational puzzles * Payment * Legal actions A strong identification of the caller, for example as described in RFC 4474 helps to mitigate SPIT. In a Public switched telephone network (PSTN), the Caller ID permits caller identification, but at least the displayed caller ID can be spoofed. Various SPIT mitigation methods and frameworks have been proposed.

Telephone prefix

prefixtelephone prefixdialing prefix
* Telephone numbering plan * List of international call prefixes * List of country calling codes eo:Telefonprefikso * Telephone numbering plan * List of international call prefixes * List of country calling codes

Dial tone

dial tonedial-tonestutter dial tone
A dial tone is a telephony signal sent by a telephone exchange or private branch exchange (PBX) to a terminating device, such as a telephone, when an off-hook condition is detected. It indicates that the exchange is working and is ready to initiate a telephone call. The tone stops when the first dialed digit is recognized. If no digits are forthcoming, the permanent signal procedure is invoked, often eliciting a special information tone and an intercept message, followed by the off-hook tone, requiring the caller to hang up and redial. Early telephone exchanges signaled the switchboard operator when a subscriber picked up the telephone handset to make a call.


NortelNortel NetworksNorthern Electric
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 numbers in Singapore

The other two major carriers, M1 and StarHub, do not offer any special dialling arrangements for calling to Malaysia and Indonesia, instead requiring full international dialling, the same as calling other countries. 3xxx xxxx - Business and Corporate IP Telephony Services 6xxx xxxx - Public Switched Telephone Network (PSTN) and Residential IP Telephony Services 8zxx xxxx - Mobile and Data Services 9yxx xxxx - Mobile, Pager (until May 2012), and Data Services 800 xxx xxxx - Toll-free international services 1800 xxx xxxx - Toll-free domestic services (Free if calling from a landline.

Timeline of the telephone

existence of a transatlantic telephonechronicles the developmenton-or-off transmission methods
* 3 April 1973: Motorola employee Martin Cooper placed the first hand-held cell phone call to Joel Engel, head of research at AT&T's Bell Labs, while talking on the first Motorola DynaTAC prototype. * 1973: packet switched voice connections over ARPANET with Network Voice Protocol (NVP). * 1976: Kazuo Hashimoto invented Caller ID * 1978: Bell Labs launched a trial of the first commercial cellular network in Chicago using Advanced Mobile Phone System (AMPS). * 1978: World's first NMT phone call in Tampere, Finland. * 1979: VoIP – NVP running on top of early versions of IP * 1981: The world's first fully automatic mobile phone system NMT is started in Sweden and Norway.

Global network

global networkglobalglobally distributed network
architecture * Global network positioning * Telephony * Fiber optic cable * Telegraphy

Telephone network

telephone networkNetwork engineeringtelephone
Virtual Network Operators (VNOs) lease capacity wholesale from the PTOs and sell on telephony service to the public directly * Telephone service (disambiguation) * A landline network where the telephones must be directly wired into a single telephone exchange. This is known as the public switched telephone network or PSTN. * A wireless network where the telephones are mobile and can move around anywhere within the coverage area. * A private network where a closed group of telephones are connected primarily to each other and use a gateway to reach the outside world. This is usually used inside companies and call centres and is called a private branch exchange (PBX).

Nepal Telecom

NTCNepal Telecom
* Lease Line Service * Basic Telephony * ISDN * GSM Cellular Telephony * Email * Internet Leased Line * Payphone * CDMA Network as SkyPhone * Wireless Loop Link * CDMA EV-DO * 3G, HSDPA * 4G LTE * Intelligent Network * Voice Mail * GPRS Service * MMS * Digital Data Network (DDN) * ADSL * WiMAX * MPOS * WiFi Hotspot * Fiber to the Home * SmartCell * Ncell * Lease Line Service * Basic Telephony * ISDN * GSM Cellular Telephony * Email * Internet Leased Line * Payphone * CDMA Network as SkyPhone * Wireless Loop Link * CDMA EV-DO * 3G, HSDPA * 4G LTE * Intelligent Network * Voice Mail * GPRS Service * MMS * Digital Data Network (DDN) * ADSL * WiMAX * MPOS

Vertical service code

vertical service codecalling featureservice feature
AT&T implementations of VSC features * Public switched telephone network * Short code * Signalling System 7 de:Vermittlungstechnische Leistungsmerkmale (öffentliche Netze) * Mobile dial code * Pat Fleet – Prompt voice for most U.S. AT&T implementations of VSC features * Public switched telephone network * Short code * Signalling System 7

Call Control eXtensible Markup Language

Combines CCXML, VoiceXML with MRCP, HTTP(s) interfaces and connects to internet protocol, fixed telephony and mobile phone telecoms networks using SIP, VOIP, SS7/PSTN and other telecoms protocols. Supports multi-tenant applications. * Open Source Oktopous PIK an abstract, C++ implementation of the W3C Call Control XML (ccXML) standard. Licensed under a BSD-Style license, the toolkit is independent of the underlying telephony platform / protocols and is best suited for OEM / System Integrators looking to implement ccXML functionality in their product offerings. Originally developed by Phonologies, Oktopous has been adopted by more telephony platforms than any open source ccXML Browser.

Telecommunications in India

TelephonecommunicationsTelegraphy and telephony
As the unbranded Chinese cell phones which do not have International Mobile Equipment Identity (IMEI) numbers pose a serious security risk to the country, Mobile network operators therefore suspended the usage of around 30 million mobile phones (about 8% of all mobiles in the country) by 30 April 2009. Phones without valid IMEI cannot be connected to cellular operators. India has opted for the use of both the GSM (global system for mobile communications) and CDMA (code-division multiple access) technologies in the mobile sector. In addition to landline and mobile phones, some of the companies also provide the WLL service. The mobile tariffs in India have also become the lowest in the world.


On April 28, 2008 Jajah provideds its proprietary telephony infrastructure, payment processing, and customer care to Yahoo! Messenger users using the platform for receiving calls from the PSTN network, or for making calls to land lines and mobile phones. Telefónica bought Jajah for a reported $207 million on December 23, 2009. On April 14, 2011, Jajah announced a partnership with Globe Telecom to allow Filipinos living outside Philippines to call home at inexpensive rate. It announced November 30, 2012 that effective January 30, 2013, Yahoo! Messenger will no longer offer Yahoo! Voice Phone In and Phone Out capabilities, the co-branded landline and mobile phone service from Jajah.

History of telecommunication

progressenormously increased speed of telecommunicationshistory of telecommunication
The first and historically most important application for communication satellites was in intercontinental long distance telephony. The fixed Public Switched Telephone Network relays telephone calls from land line telephones to an earth station, where they are then transmitted a receiving satellite dish via a geostationary satellite in Earth orbit. Improvements in submarine communications cables, through the use of fiber-optics, caused some decline in the use of satellites for fixed telephony in the late 20th century, but they still exclusively service remote islands such as Ascension Island, Saint Helena, Diego Garcia, and Easter Island, where no submarine cables are in service.

Foreign exchange service (telecommunications)

foreign exchange stationforeign exchange officeforeign exchange line
These are commonly found in devices acting as gateways between local Voice over Internet Protocol (VoIP) systems and the public switched telephone network (PSTN). In a nutshell, an FXO device is any device that, from the point of view of a telephone exchange, appears to be a regular telephone. As such, it should be able to accept ringing signals, go on-hook and off-hook, and send and receive voice frequency signals. It may use loop start or ground start signaling. FXO channel units were invented and named in the middle 20th century for service at the "Office" end of an FX line via carrier system.

UK telephone code misconceptions

misquotedSimilar misunderstandingswidespread misconception
From 1997 new numbers began to be issued whose local 7-digit string began with a number other than 9, starting with 3xx-xxxx: * 1) 1997 Local numbers beginning with 3 introduced * 2) 2007 Local numbers beginning with 2 introduced * 3) 2012 Local numbers beginning with 4 introduced The United Kingdom adopts an open dialling plan for area codes within its public switched telephone network. Therefore, all area codes have a preceding "0" when dialling from within the United Kingdom. When dialling a UK number from abroad, the zero must be omitted.


modemmodemsdial-up modem
Direct broadcast satellite, WiFi, and mobile phones all use modems to communicate, as do most other wireless services today. Modern telecommunications and data networks also make extensive use of radio modems where long distance data links are required. Such systems are an important part of the PSTN, and are also in common use for high-speed computer network links to outlying areas where fibre is not economical. Even where a cable is installed, it is often possible to get better performance or make other parts of the system simpler by using radio frequencies and modulation techniques through a cable.

Voice over IP

VoIPvoice over IPvoice over Internet Protocol
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).

Mobile telephony

mobile telephonymobile communicationmobile communications
Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Mobile phones connect to a terrestrial cellular network of base stations (cell sites), whereas satellite phones connect to orbiting satellites. Both networks are interconnected to the public switched telephone network (PSTN) to allow any phone in the world to be dialed. In 2010 there were estimated to be five billion mobile cellular subscriptions in the world.

GSM services

mobile data servicewireless mobile dataservices
The systems that monitor and provide the prepaid services are not part of the GSM standard services, but instead an example of intelligent network services that a mobile phone operator may decide to implement in addition to the standard GSM ones. When someone places a call to a mobile phone, they dial the telephone number (also called a MSISDN) associated with the phone user and the call is routed to the mobile phone operator's Gateway Mobile Switching Centre. The Gateway MSC, as the name suggests, acts as the "entrance" from exterior portions of the Public Switched Telephone Network onto the provider's network.