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 subscriber identity module or subscriber identification module (SIM), widely known as a SIM card, is an integrated circuit that is intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices. It is also possible to store contact information on many SIM cards. SIM cards are always used on GSM phones; for CDMA phones, they are needed only for LTE-capable handsets. SIM cards can also be used in satellite phones, smart watches, computers, or cameras.
A SIM lock, simlock, network lock, carrier lock or (master) subsidy lock is a technical restriction built into GSM and CDMA mobile phones by mobile phone manufacturers for use by service providers to restrict the use of these phones to specific countries and/or networks. This is in contrast to a phone that does not impose any SIM restrictions.
Celcom Axiata Berhad, DBA Celcom, is the oldest mobile telecommunications provider in Malaysia. Celcom is a member of the Axiata group of companies.
Gruppo TIM is an Italian telecommunications company with headquarters in Rome, Milan, and Naples, which provides telephony services, mobile services, and DSL data services. It is the largest Italian telecommunications services provider in revenues and subscribers. It was founded in 1994 by the merger of several state-owned telecommunications companies, the most prominent of which was Società Italiana per l'Esercizio Telefonico S.p.A.,, the former state monopoly telephone operator in Italy.
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 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/Intelligent Network. Users can top up their credit at any time using a variety of payment mechanisms.
TracFone Wireless, Inc. (TFWI) is an American prepaid, no-contract mobile phone provider. TFWI is a subsidiary of Mexico's largest telecommunications company, América Móvil, and offers products and services under several brands. It operates as a mobile virtual network operator (MVNO), holding agreements with the United States' largest wireless network operators to provide service, including Verizon Wireless, AT&T Mobility, T-Mobile US, Sprint Corporation, and U.S. Cellular. TracFone Wireless had 25.668 million subscribers in 2015.
Vodafone Greece is the Greek subsidiary of Vodafone. Its headquarters are in Halandri - one of the northern suburbs of Athens.
Wind Hellas is an integrated telecommunications provider with headquarters in Athens, Greece. Wind is the third largest mobile operator in Greece with more than 4.4 million active subscribers. The actual numbers for the years after 2015 are confidential but according to the report of Greek Government for the year 2017, Wind has a share of 15-25% of active subscribers of mobile telephony and 10-15% share of active subscribers of fixed telephony. The Display name of WIND: WIND GR while for Q-telecom is: Q-TELECOM or Q-TELCOM
SLTMobitel is the national telecommunications services provider in Sri Lanka and one of the country’s largest companies with an annual turnover in excess of Rs 40 billion. The company provides domestic and corporate services which include fixed and wireless telephony, Internet access and IT services to domestic, public and business sector customers.
Emtel Ltd. is a telecommunications company based in Ebene City, Mauritius. Launched on 29th May 1989 – Emtel Ltd became the first mobile telephony operator in the Southern Hemisphere. This major step in Mauritian telecommunications history took place under the aegis of The Currimjee Jeewanjee Group, which is one of the leading groups in Mauritius. From a mobile company, Emtel has evolved into a one-stop shop for all your telecommunications needs, offering a wide range of products and services for individuals, enterprises and homes. Emtel’s innovations include the first 3G network in Africa in 2004. Since 27th April 2015, Emtel holds a partnership with Airtel, India’s leading provider of prepaid & postpaid, wireless internet, broadband, fixed line, digital TV and mobile services. Today with 4G and FTTB services, it is one of the most technologically advanced operators in Africa.
Hellas Online was one of the leading Greek fixed-line telephony service providers based in Athens. Founded in 1993, Hellas Online (hol) was one of the first Internet service providers in Greece offering public dial-up Internet access. It evolved from an ISP to a fixed-line telecommunications services provider offering a broad range of retail, business and wholesale services. Since 2006 it became a member of the Intracom Holdings group. Before its dissolution, following its merger, with Vodafone in 2014, it had 531,563 LLU subscribers.
The history of the prepaid mobile phone began in the 1990s when mobile phone operators sought to expand their market reach. Up until this point, mobile phone services were exclusively offered on a postpaid basis (contract-based), which excluded individuals with poor credit ratings and minors under the age of 18.
Brightroam is a deep discount international roaming mobile provider owned by iRoam Mobile Solutions a subsidiary of Sea Change Corporation. The company is headquartered in Toronto, Ontario, Canada and provides global cellular communications to corporations and individuals at reduced costs associated with international roaming.
With prepaid mobile phone service, topping-up or reloading is needed to continue using the services of the operator. There are several ways to reload a prepaid mobile phone. The most popular process is through purchasing a prepaid card but, due to security precautions, and for convenience, electronic reloading was developed.
MTS M Blaze is an EVDO based services provided by ‘’’MTS India’’’. MTS launched EVDO Rev A based high-speed mobile broadband service, MBlaze, in November 2009 and has seen tremendous market acceptance with over 5,00,000 customers in a short span of time. In April 2010, MTS launched MTS TV for MTS MBlaze customers. MTS MBlaze have its coverage in 100+ cities as of February 2011. MTS has also announced pan-India roaming for its users in April–May 2010. MTS also provides MBrowse which is CDMA-1x technology based internet service.
3G mobile telephony was relatively slow to be adopted globally. In some instances, 3G networks do not use the same radio frequencies as 2G so mobile operators must build entirely new networks and license entirely new frequencies, especially so to achieve high data transmission rates. Other delays were due to the expenses of upgrading transmission hardware, especially for UMTS, whose deployment required the replacement of most broadcast towers. Due to these issues and difficulties with deployment, many carriers were not able to or delayed acquisition of these updated capabilities.
ABS-CBN Mobile was a cellular telephony service provider in the Philippines owned and operated by ABS-CBN Convergence, a subsidiary of ABS-CBN. ABS-CBNmobile formerly uses the network infrastructures of Globe Telecom under a network-sharing agreement which allows ABS-CBN and Globe to share frequencies, switches, servers, and transmitters. ABS-CBNmobile formerly offers prepaid and postpaid SMS, voice, data, wireless landline connection, and access to premium and exclusive contents of iWant TV.
