Technical data

WMO2 G900 / G1800 / G1900
WCOM/GSM/WMO2/WMO2ATDOC Friday 21 May 1999
WAVECOM confidential © 69
4.9 V24-V25 commands
4.9.1 Fixed DTE rate +IPR
This commands specifies the data rate at which the DCE will accept
commands.
Application to GSM AT+IPR?
GSM to application +IPR: 9600
OK
current rate is 9600 bps
Application to GSM AT+IPR=?
GSM to application +IPR:(0,2400, 4800, 9600, 19200) ,
(300,600,38400,57600,115200)
OK
possible values (1)
Application to GSM AT+IPR=38400
GSM to application OK disable autobauding and set
rate to 38400 bps
Application to GSM AT+IPR=0
GSM to application OK enable autobauding
Note (1): first set of values indicates the range of autodetectable speeds.
The second set of values indicates all the possible speeds which can be
used by DCE.
An autobauding is provided which operates from 2400 to 19200 baud.
However some constraints have to be dealt with:
• any AT command issued by DTE must start with a capital ‘A’ and
‘T’ (or ‘\’). If not, DCE may send back some garbagge characters
and get de-synchronized. Shoud it happen, DTE shall just issue
once or twice ‘AT\r’ (at 2400 or 4800 baud) or just ‘AT’ (at 9600
baud) to get the modem re-synchronized.
• the DTE shall wait for 1ms after receipt of the last character of the
AT response (which is always ‘\n’ or 0x0A) to send a new AT
command at either the same rate or a new rate. Shoud this delay
ignored, DCE can get de-synchronised. Once again, sending once
or twice ‘AT\r’ or just ‘AT’ causes the DCE to recover.
Be careful: at start-up if autobauding is enabled and no AT command has
been received yet, the module sends all unsolicited responses (like RING) at
9600 baud.