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the remote modem, implementing the V.42 protocol, the International Telecommunications
Union (ITU) standard for error correction.
12.4.5 Fax
Sending a fax is very similar to sending data. To send a fax, an initial call is made to the
network. The call is then routed through the network to the GIWU. The GIWU then
establishes a connection to the remote fax machine. The fax protocols are than passed end
to end between the mobile terminal and the remote fax machine.
12.4.6 SMS Services
The Ericsson Mobile Companion is capable of sending and receiving SMS messages, using the
Inbox software. With the Short Message Service, a user can send text messages containing up to
160 characters to and from GSM mobile stations. A Service Centre (SC) acts as a store and forward
centre.
SMS consists of two basic services:
•
Mobile Originated SMS (from a Mobile Station to a SMS-C)
•
Mobile Terminated SMS (from a SMS-C to a Mobile Station)
For Mobile Orginated SMS, an SMS message is sent from a Mobile Station to the SMS-C where it
is forwarded to its destination. This can be another Mobile Station, or a terminal in the fixed
network.
A Mobile Terminated SMS is when an SMS message is forwarded from the SMS-C to a Mobile
Station. When the Mobile Station receives the message, it returns a delivery report saying the
transfer was successful.