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GSM -> Services Provided by GSMFrom the beginning, the planners of GSM wanted ISDN compatibility in services offered and control signalling used. The radio link imposed some limitations, however, since the standard ISDN bit rate of 64 kbps could not be practically achieved. |
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| Using the ITUT definitions, telecommunication services can be divided into
bearer services, teleservices, and supplementary services. The
digital nature of GSM allows data, both synchronous and asynchronous, to be
transported as a bearer service to or from an ISDN terminal. Data
can use either the transparent service, which has a fixed delay but no guarantee
of data integrity, or a nontransparent service, which guarantees data
integrity through an Automatic Repeat Request (ARQ) mechanism, but with a
variable delay. The data rates supported by GSM are 300 bps, 600
bps, 1200 bps, 2400 bps, and 9600 bps .
The most basic teleservice supported by GSM is telephony. There is an emergency service, where the nearest emergencyservice provider is notified by dialling three digits (similar to 911). |
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Group 3 fax, an analog method described in ITUT recommendation T.30, is also supported by use of an appropriate fax adaptor. A unique feature of GSM compared to older analog systems is the Short Message Service (SMS). SMS is a bidirectional service for sending short alphanumeric (up to 160 bytes) messages in a storeandforward fashion. For pointtopoint SMS, a message can be sent to another subscriber to the service, and an acknowledgement of receipt is provided to the sender. SMS can also be used in a cellbroadcast mode, for sending messages such as traffic updates or news updates. Messages can be stored in the SIM card for later retrieval . Supplementary services are provided on top of teleservices or bearer services, and include features such as caller identification, call forwarding, call waiting, multiparty conversations, and barring of outgoing (international) calls, among others.
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<<<What is GSM? GSM Architecture>>>
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