Multi-Tech Systems GPRS (MTMMC-G) User Manual

Chapter 2 – AT Command Features 

Multi-Tech Systems, Inc. Wireless GSM/GPRS AT Commands (Document Number S000293I) 

10 

 

A serial link handler is set with the following default values (factory settings):  

• 

Autobaud 

• 

8 bits data 

• 

1 stop bit 

• 

no parity 

• 

RTS/CTS flow control 

 Please use the +IPR, +IFC and +ICF commands to change these settings. 

Commands always start with 

AT (which means ATtention) and finish with a <CR> character.  

Responses start and end with <CR><LF>, except for the ATV0 DCE response format and the ATQ1 (result code 
suppression) commands. 

• 

If the command syntax is incorrect, an 

ERROR string is returned. 

• 

If the command syntax is correct but transmitted with the wrong parameters, the 

+CME ERROR: <Err> or +CMS 

ERROR: <SmsErr> strings are returned with adequate error codes if the CMEE was previously set to 1. By 
default, CMEE us set to 0, and the error message is only “ERROR”. 

• 

If the command line has been performed successfully, an 

OK string is returned. 

In some cases, such as “AT+CPIN?” or (unsolicited) incoming events, the product does not return the

 OK string as a 

response.