
MODEM AND AT COMMANDS
The T39 contains a complete GSM modem. This provides data and
In the T39, AT commands are used both for:
•controlling the data communication between the PC and the remote service
•configuring and requesting settings and behaviours in the phone, from a connected PC or
PDA
GSM Data Communication
The
A normal GSM call only uses one of eight repeating time slots in the GSM channel, giving a data speed of 9,600 bps. The T39 supports a more efficient coding scheme, giving data speeds of up to 14,400 bps (providing the network supports this).
9,600/14,400
9,600/14,400
9,600/14,400
9,600/13,200
9,600/13,200
9,600/13,200
9,600/13,200
1
GSM 9,600 bps
14,400, 19,200 or 28,800 bps (HSCSD)
2
GPRS
9,600, 13,200, 19,200, 26,400, 28,800 or 39,600 bps
High Speed Data Gives A Faster Speed
High Speed Circuit Switched Data (HSCSD) gives the possibility to use two time slots for receiving data. In combination with a more efficient coding scheme, this can increase the receiving data speed up to 28,800 bps
GPRS Enables Constant Connection And High Speed
With GPRS, the connection is maintained “constantly”, and data is transmitted in packets. Pric- ing of GPRS can be dependent on the actual use of bandwidth, which means very low cost when no data is sent or received, while the phone remains connected. When transmitting large amounts of data, bandwidth can be increased automatically to allow faster transmission speed, up to 39,600 bps download speed.
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