Network switching subsystem

HLRMSCHome Location Register
Network switching subsystem (NSS) (or GSM core network) is the component of a GSM system that carries out call out and mobility management functions for mobile phones roaming on the network of base stations. It is owned and deployed by mobile phone operators and allows mobile devices to communicate with each other and telephones in the wider public switched telephone network (PSTN). The architecture contains specific features and functions which are needed because the phones are not fixed in one location. The NSS originally consisted of the circuit-switched core network, used for traditional GSM services such as voice calls, SMS, and circuit switched data calls.

List of Fonejacker episodes

Complete Series 1
The following is an episode list for the E4 series Fonejacker. The series premiered on Comedy Lab with a pilot episode, and due to much popularity, a full series started on 5 July 2007, although the series was originally going to be aired in April at some point, but was delayed. A Christmas special was aired on 20 December of the same year. Then, in 2008, a second series began on 18 September. Both series have been released on DVD including special features such as Unseen Material and audio commentaries. Each episode is approximately 23 minutes long.

Operator Toll Dialing

Nationwide Operator Toll Dialing
Operator Toll Dialing was a project and method used by the Bell System in the USA and Canada to automate the switching and billing of long distance calls in the public switched telephone network (PSTN). The program was initiated by 1945, at which time ca. 5% of the 2.7 million toll board calls per day were handled by this method. Operator Toll Dialing eliminated the need for intermediate and inward operators to complete toll calls to distant central offices. Initially this system involved step-by-step routings to set up each circuit, but later was improved by the development of area codes with machine translation which helped to standardize dialing across the network.

List of international call prefixes

International call prefixinternational access code+
List of country calling codes. List of mobile phone number series by country. List of North American Numbering Plan area codes. Public switched telephone network. Standards and recommendations. List of International Call Prefixes.

Soundboard (computer program)

In some cases, the victim associated with the prank call has no idea who the person from the soundboard is, with one famous example being Matt Romney pranking his father by pretending to be Arnold Schwarzenegger using a sound board. Some users even record the calls and post them on the Internet. Soundboard prank-calling is often done with caller ID spoofing or masking, to provide a high level of anonymity or impersonation. The goal is often to create confusion or test how long the victim(s) will remain on the phone.

List of confidence tricks

grandparent scambig storebig stores
A similar caller ID spoofing scheme exists with misleading telephone calls ("vishing") facilitated by Internet telephony. A fraudster can make calls through an Internet-PSTN gateway to impersonate banks, police, schools or other trusted entities. A random dialer computer or auto-dialer can impersonate healthcare providers to get Social Security numbers and birthdates from elderly patients recently released from the hospital. The auto-dialer call states it is from a reputable hospital or a pharmacy and the message explains the need to "update records" to be from the hospital or a pharmacy.

Area code 600

. * Telephone numbers in Canada * Non-geographic Telephone Codes for North America

Cable modem

cablecable modemscable internet
The earliest systems used the public switched telephone network (PSTN) for the return path since very few cable systems were bi-directional. Later systems used CATV for the upstream as well as the downstream path. Hybrid's system architecture is used for most cable modem systems today. LANcity was an early pioneer in cable modems, developing a proprietary system that was widely deployed in the U.S. LANcity, which was led by the Iranian-American engineer Rouzbeh Yassini, was then acquired by Nortel, which eventually spun the cable modem business off as ARRIS. ARRIS continues to make cable modems and CMTS equipment compliant with the DOCSIS standard.

Area codes 919 and 984

919984919, 984
In 1993, the eastern and southern portions of the numbering plan area were split off to form area code 910. In 1998, the northeastern portion was split off to form area code 252. Area code 919 was initially slated for overlay with area code 984 in 2001. However, the overlay was deferred when the supply of numbers was deemed sufficient for the near term. Within a decade, however, the proliferation of cell phones and pagers meant that the implementation of 984 could no longer be delayed. In September 2011, the North Carolina Utilities Commission announced that the 984 area code was being pressed into service.

Quality of service

QoSquality-of-serviceQuality of Service (QOS)
Mobile cellular service providers may offer mobile QoS to customers just as the fixed line PSTN services providers and Internet Service Providers (ISP) may offer QoS. QoS mechanisms are always provided for circuit switched services, and are essential for non-elastic services, for example streaming multimedia. Mobility adds complication to the QoS mechanisms, for several reasons: Quality of service in the field of telephony, was first defined in 1994 in the ITU-T Recommendation E.800. This definition is very broad, listing 6 primary components: Support, Operability, Accessibility, Retainability, Integrity and Security.

Routing in the PSTN

routingalternate routecall routing
Routing in the PSTN is the process used to route telephone calls across the public switched telephone network. Telephone calls are routed across a network of potentially many switching systems, often owned by different telephone carriers. Switching systems are connected with trunks. Each switch may have many neighbors. Neighboring switches owned by different operators are connected at interconnect points. The PSTN is not a full mesh network with the nodes of every operator directly connected to those of every other, which would be impractical and inefficient. Therefore, calls may be routed through intermediate operator networks before they reach their final destination.


In telephony, a customer's telephone line now typically ends at the remote concentrator box, where it is multiplexed along with other telephone lines for that neighborhood or other similar area. The multiplexed signal is then carried to the central switching office on significantly fewer wires and for much further distances than a customer's line can practically go. This is likewise also true for digital subscriber lines (DSL). Fiber in the loop (FITL) is a common method of multiplexing, which uses optical fiber as the backbone. It not only connects POTS phone lines with the rest of the PSTN, but also replaces DSL by connecting directly to Ethernet wired into the home.

Springfield (The Simpsons)

SpringfieldShelbyvilleSpringfield Elementary
Burns believes in order to operate a telephone, you spell the requested person's name out using the alphabetic keypad (he spells out S-M-I-T-H-E-R-S), he is instead connected to Moe's Tavern. As a result, if one was to spell Smithers name out on a telephone keypad, the fictional phone number minus the area code for the tavern would be revealed as 764-8437(7). Moe and his tavern had been the victim of Bart's ongoing prank calls in the earlier seasons when Bart would call looking for nonexistent people with names that would get Moe laughed at by his customers. Though there was one name that backfired on Bart when he asked for Hugh Jass, who had been sitting in the tavern.

Plain old telephone service

POTSLocal Telephone Servicetelephone
In most cases, the function of the local loop presented to the customer for connection to telephone equipment is practically unchanged and remains compatible with pulse dialing telephones. Due to the wide availability of traditional telephone services, new forms of communications devices such as modems and facsimile machines were initially designed to use traditional analog telephony to transmit digital information. Although POTS provides limited features, low bandwidth, and no mobile capabilities, it provides greater reliability than other telephony systems (mobile phone, VoIP, etc.).


Niue is a very small island country with a population of about 1,700 - too small to attract mobile telecommunications providers. The cost structure of OpenBTS suited Niue, which required a mobile phone service but did not have the volume of potential customers to justify buying and supporting a conventional GSM basestation system. The success of this installation and the demonstrated demand for service helped bootstrap later commercial services.

Speech coding

speech codecspeech encodingspeech
Mobile phone. Pulse-code modulation. Psychoacoustic model. Speech interface guideline. Speech processing. Speech synthesis. Telecommunication. Vector quantization. Vocoder. Various Speech Coding Links. ITU-T Test Signals for Telecommunication Systems Test Samples. ITU-T Perceptual evaluation of speech quality (PESQ) tool Sources.


keyboardkeypadsnumeric keypad
Additionally, on a rotary telephone, the "1" hole was at the top, albeit at the top right. Keyboard (computing). Telephone keypad. Push-button telephone. Silicone rubber keypad. Numeric keypad. Keyboard technology. Mobile phone. Digital door lock. Arrow keys.

Managed facilities-based voice network

A managed facilities-based voice network (MFVN) is a physical network owned and operated by a voice service provider that delivers traditional telephone service via a loop start analog telephone interface. MFVNs are interconnected with the public switched telephone network (PSTN) and provide dialtone to end users. Historically, this was provided by equipment at Bell company central offices, however today's MFVNs can include a combination of access network (last mile network of copper, coaxial cable, or fiber optics), customer premises equipment (CPE), network switches and routers, network management systems, voice call servers, and gateways to the larger PSTN.


GlobalStar-2failures of the Globalstar network's satellitesGlobalstar 7
Voice Telephony. One-way mobile-terminated SMS text messaging. 9,600 bit/s circuit-switched data calls. 9,600 bit/s packet-switched Internet access. One-way mobile originated short-burst messages (simplex devices only). Device geolocation within approximately 30 km. Mobile-satellite service. Satellite phone. Broadband Global Area Network. Gonets. ICO Satellite Management. Inmarsat. Iridium Satellite LLC. O3b. SkyWave Mobile Communications. Starlink (SpaceX). Teledesic. TerreStar. Thuraya. Thales Alenia Space. Orbcomm.


mnemoniclettersphone word
On older landline telephones, the O, Q and Z sometimes vary in placement or are omitted entirely; this is not an issue for most mobile telephones as all 26 letters must be provided to support short message service transmission. The dialing of 1 or 0 instead of I or O in phonewords can lead to misdialed calls; one such typosquatting incident targeted 1-800-HOLIDAY (+1-800-465-4329, the toll-free direct reservations line for Holiday Inn) by subscribing 1-800-H0LIDAY (+1-800-405-4329, the same number with 'o' replaced by 'zero') to a rival vendor which stood to collect a profitable travel agent's commission.

Push-button telephone

10- or 12-button touch-tone telephonespush-buttonpush-button dialing
Like cellular handsets, telephones designed for voice-over-IP use out-of-band signaling to send the dialed number. History of the telephone. Interactive voice response. Mobile phone. Timeline of the telephone. VoIP.

Obscene phone call

Telephone scatologialewd phone callsobscene telephone calls
Prank call. Sexual harassment. Strip search phone call scam. Why do some men make obscene phone calls?. Fact Sheet 3: How to Put an End to Unwanted or Harassing Phone Calls.


trunktrunk linetrunks
Examples of this include telephone systems and the two-way radios commonly used by police agencies. Trunking, in the form of link aggregation and VLAN tagging, has been applied in computer networking as well. A trunk is a single communications channel between two points, each point being either the switching center or the node. A trunk line is a circuit connecting telephone switchboards (or other switching equipment), as distinguished from local loop circuit which extends from telephone exchange switching equipment to individual telephones or information origination/termination equipment. Trunk lines are used for connecting a private branch exchange (PBX) to a telephone service provider.

Digital electronics

digital circuitdigitaldigital technology
An increasingly common goal is to reduce the power used in a battery-powered computer system, such as a cell-phone. Many computer architects serve an extended apprenticeship as microprogrammers. Digital circuits are made from analog components. The design must assure that the analog nature of the components doesn't dominate the desired digital behavior. Digital systems must manage noise and timing margins, parasitic inductances and capacitances, and filter power connections.

Video game

video gamesgamevideogame
For casual online puzzle-style and simple mobile cell phone games, the gender divide is more or less equal between men and women. More recently there has been a growing segment of female players engaged with the aggressive style of games historically considered to fall within traditionally male genres (e.g., first-person shooters). According to the ESRB, almost 41% of PC gamers are women. Participation among African-Americans is lower. One survey of over 2000 game developers returned responses from only 2.5% who identified as black. When comparing today's industry climate with that of 20 years ago, women and many adults are more inclined to be using products in the industry.