Rainbow Electronics GM862-GPS - Manual (Page 13)

GM862-GPS Software User Guide
1vv0300729 Rev. 5 - 05/07/07
Reproduction forbidden w ithout Telit Communications S.p.A. w ritten authorization - All Rights Reserved page 13 of 120
2.5 Checking GSM device functionality
After a proper power on the device is ready to receive AT commands on the serial port.
Several things have to be checked in order to be sure that the device is ready to send and receive
calls and SMS:
2.5.1 Autobauding
At startup it is necessary to send an AT command to make the device set the right speed and
character format of the serial port. When this is done the device responds with OK. If no response is
received within the timeout period of 200 ms retry.
•
Send command AT<cr>
•
wait for OK response
after this initial command, it is advisable to fix the port rate, in order to eliminate possible errors in
detecting the serial speed rate:
•
Send command
AT+IPR=<rate><cr>
•
wait for
OK
response
where rate is the port speed and can be 0, 300,1200,2400,4800,9600,19200,38400,57600,115200
bps.
If <rate> is set to 0, then automatic speed detection is enabled and also character format (see +ICF)
is set to auto-detect. (default)
If <rate> is specified and not 0, DTE-DCE speed is fixed at that speed, hence no speed auto-detection
(autobauding) is enabled.
TIP: The serial port suggested setting is: port speed 38400, character format 8N1 (8 bit per
char, No parity bit, 1 stop bit).
In case of an application that uses only 3 wires for the serial communication (RX, TX and GND)
it is suggested to disable the hardware flow control using the AT&K0 command.