Multi-Tech Systems MMCModem GPRS (MTMMC-G) - Manual (Page 99)

Chapter 12 – V.24 and V.25 Commands
Multi-Tech Systems, Inc. Wireless GSM/GPRS AT Commands (Document Number S000293I) 99
Chapter 12 – V.24 and V.25
Commands
Important
All commands described hereafter will to the currently selected (and used) UART.
Fixed DTE Rate +IPR
Description: This commands specifies the data rate at which the DCE will accept commands.
Notes:
• The serial autobauding feature is supported and covers the following serial speeds only:
2400, 4800, 9600, 19200, 38400, 57600 bps. Beyond those serial speeds, proper operation of
the modem is not guaranteed.
•
Any AT command issued by the DTE must start with both capital ‘A’ and ‘T’ (or ‘/’) or both lower
case ‘a’ and ‘t’ (or ‘/’); otherwise, the DCE may return some garbage characters and become
desynchronized. Should this happen, the DTE simply issues ‘AT\r’ (at 2400 or 4800 bauds) once
or twice or just ‘AT’ (at 9600 bauds) to resynchronize the modem.
• The DTE waits for 1ms after receiving 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. Should this delay be
ignored, the DCE can become desynchronised. Once again, sending ’AT\r’ once or twice or just
‘AT’ causes the DCE to recover.
Caution: When starting up, if autobauding is enabled and no AT command has yet been received, the
product sends all unsolicited responses (like RING) at 9600 bauds.
Values: Baud rates that can be used by the DCE
0 Enables autobauding
300
600
1200
2400
4800
9600
19200
38400
57600
115200
Syntax: Command syntax: AT+IPR=
Command Possible responses
AT+IPR?
+IPR: 9600
OK
Note: Current rate is 9600 bps
AT+IPR=?
+IPR: (0,2400,4800,9600,19200,38400,57600,115200), (300,600,1200)
OK
Note: Possible values, according to V25ter Recommendation:
The first set of values indicates the range of auto-detectable baud rates (including
0). The second set of values indicates the baud rates supported by the DCE but not
auto-detectable.
AT+IPR=38400
OK
Note: Disable autobauding and set rate to 38400 bps
AT+IPR=0
OK
Note: Enable autobauding