Basic AT Commands for SIM900A GSM/GPRS Module

command

TO CHECK THE MODEM:

AT

OK

TO CHANGE SMS SENDING MODE:

AT+CMGF=1

OK

TO SEND NEW SMS:

AT+CMGS="MOBILE NO."

<MESSAGE

{CTRL+Z}

PREFERRED SMS MESSAGE STORAGE:

AT+CPMS=?

+CPMS: ("SM"),("SM"),("SM")

OK

AT+CPMS?

+CPMS: "SM",19,30,"SM",19,30,"SM",19,30

TO MAKE A VOICE CALL:

ATD9876543210;

TO REDIAL LAST NO:

ATDL

TO RECEIVE INCOMING CALL:

ATA

TO HANGUP OR DISCONNECT A CALL:

ATH

TO SET A PARTICULAR BAUDRATE:

AT+IPR=?         {To view the baud rate values}

AT+IPR=0         {To set the modem to autobauding mode}

OPERATOR  SELECTION:

AT+COPS=?

OK

AT+COPS?

+COPS: 0,0,"AirTel"

OK

AT+CRC SET CELLULAR RESULT CODES FOR INCOMING CALL INDICATION:

AT+CRC=?

+CRC: (0-1)

OK

AT+CRC?

+CRC: 0

OK

AT+CRC=1

OK

+CRING: VOICE

READ OPERATOR NAMES.

AT+COPN=?

OK

AT+COPN

+COPN: "472001","DHIMOBILE"

+COPN: "60500

+COPN: "502012","maxis mobile"

+COPN:

+COPN: "502013","TMTOUCH"

+COPN

+COPN: "502016","DiGi"

+COPN: "502017","TIMECel""

+COPN: "502019","CELCOM GSM"
GPRS COMMANDS:

Command Description

AT+CGATT                   ATTACH/DETACH FROM GPRS SERVICE

AT+CGDCONT             DEFINE PDP CONTEXT

AT+CGQMIN               QUALITY OF SERVICE PROFILE (MINIMUM ACCEPTABLE)

AT+CGQREQ               QUALITY OF SERVICE PROFILE (REQUESTED)

AT+CGACT                   PDP CONTEXT ACTIVATE OR DEACTIVATE

AT+CGDATA                ENTER DATA STATE

AT+CGPADDR              SHOW PDP ADDRESS

AT+CGCLASS               GPRS MOBILE STATION CLASS

AT+CGEREP                 CONTROL UNSOLICITED GPRS EVENT REPORTING

AT+CGREG                  NETWORK REGISTRATION STATUS

AT+CGSMS                  SELECT SERVICE FOR MO SMS MESSAGES

AT+CGCOUNT                         GPRS PACKET COUNTERS

https://www.pantechsolutions.net/wireless-boards/sim900a-gsm-modem