Short Message/Messaging Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile devices exchange short text messages. An intermediary service can facilitate a text-to-voice conversion to be sent to landlines.
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for voice calls for the delivery of voice communication sessions over Internet Protocol (IP) networks, such as the Internet.
The international mobile subscriber identity (IMSI) is a number that uniquely identifies every user of a cellular network. It is stored as a 64-bit field and is sent by the mobile device to the network. It is also used for acquiring other details of the mobile in the home location register (HLR) or as locally copied in the visitor location register. To prevent eavesdroppers from identifying and tracking the subscriber on the radio interface, the IMSI is sent as rarely as possible and a randomly-generated TMSI is sent instead.
A SIM card is an integrated circuit (IC) intended to securely store an international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephone devices. Technically the actual physical card is known as a universal integrated circuit card (UICC); this smart card is usually made of PVC with embedded contacts and semiconductors, with the SIM as its primary component. In practice the term "SIM card" refers to the entire unit and not simply the IC.
Roaming is a wireless telecommunication term typically used with mobile devices, such as mobile phones. It refers to a mobile phone being used outside the range of its native network and connecting to another available cell network.
In telecommunications, a callback or call-back occurs when the originator of a call is immediately called back in a second call as a response.
Mobility management is one of the major functions of a GSM or a UMTS network that allows mobile phones to work. The aim of mobility management is to track where the subscribers are, allowing calls, SMS and other mobile phone services to be delivered to them.
Network switching subsystem (NSS) 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.
Unstructured Supplementary Service Data (USSD), sometimes referred to as "quick codes" or "feature codes", is a communications protocol used by GSM cellular telephones to communicate with the mobile network operator's computers. USSD can be used for WAP browsing, prepaid callback service, mobile-money services, location-based content services, menu-based information services, and as part of configuring the phone on the network. The service does not require a messaging app, and does not incur charges.
GSM services are a standard collection of applications and features available over the Global System for Mobile Communications (GSM) to mobile phone subscribers all over the world. The GSM standards are defined by the 3GPP collaboration and implemented in hardware and software by equipment manufacturers and mobile phone operators. The common standard makes it possible to use the same phones with different companies' services, or even roam into different countries. GSM is the world's most dominant mobile phone standard.
A prepaid mobile device, also known as a pay-as-you-go (PAYG), pay-as-you-talk, pay and go, go-phone, prepay or burner phone, is a mobile device such as a phone for which credit is purchased in advance of service use. The purchased credit is used to pay for telecommunications services at the point the service is accessed or consumed. If there is no credit, then access is denied by the cellular network or Intelligent Network. Users can top up their credit at any time using a variety of payment mechanisms.
A mobile phone feature is a capability, service, or application that a mobile phone offers to its users. Mobile phones are often referred to as feature phones, and offer basic telephony. Handsets with more advanced computing ability through the use of native code try to differentiate their own products by implementing additional functions to make them more attractive to consumers. This has led to great innovation in mobile phone development over the past 20 years.
Wi-Fi calling refers to mobile phone voice calls and data that are made over IP networks using Wi-Fi, instead of the cell towers provided by cellular networks. Using this feature, compatible handsets are able to route regular cellular calls through a wireless LAN (Wi-Fi) network with broadband Internet, while seamlessly change connections between the two where necessary. This feature makes use of the Generic Access Network (GAN) protocol, also known as Unlicensed Mobile Access (UMA).
Mobile VoIP or simply mVoIP is an extension of mobility to a voice over IP network. Two types of communication are generally supported: cordless telephones using DECT or PCS protocols for short range or campus communications where all base stations are linked into the same LAN, and wider area communications using 3G or 4G protocols.
Truphone is a GSMA-accredited global mobile network that operates its service internationally. The company is headquartered in London and has offices in ten other countries, being spread across four continents.
Asda Mobile is a mobile virtual network operator (MVNO) in the United Kingdom operated by Asda and using the Vodafone network. Asda Mobile is available in over 360 stores across the UK and online through purchasing either a SIM card or through an Asda Mobile handset.
A virtual number, also known as direct inward dialing (DID) or access numbers, is a telephone number without a directly associated telephone line. Usually, these numbers are programmed to forward incoming calls to one of the pre-set telephone numbers, chosen by the client: fixed, mobile or VoIP. A virtual number can work like a gateway between traditional calls (PSTN) and VoIP.
A mobile broadband modem, also known as wireless modem or cellular modem, is a type of modem that allows a personal computer or a router to receive wireless Internet access via a mobile broadband connection instead of using telephone or cable television lines. A mobile Internet user can connect using a wireless modem to a wireless Internet Service Provider (ISP) to get Internet access.
FreedomPop is a wireless Internet and mobile virtual network operator based in Los Angeles, California. The company provides "free" IP mobile services including free data, text and VoIP and sells mobile phones, tablets and broadband devices for use with their service. It was founded by CEO Stephen Stokols and Steven Sesar, and owned and operated by STS Media Inc until June 2019 when it was successfully sold. FreedomPop uses networks of T-Mobile and AT&T in the United States, Three in the UK, Yoigo in Spain, and Telcel in Mexico.
