The CALL READY message from the SIM900 indicates that the modem is powered up and has acquired a valid network. Next thing is to make sure you have set the SIM900 into TEXT mode by sending the command AT+CMGF=1; followed by a carriage return(rn).
If you are facing any problem with respect to modem not responding to commands read my previous article to solve it.. it applies to SIM900 problems too.
Reading a SMS message from the Inbox:
- To read the first SMS from the inbox send the command AT+CMGR=1 followed by rn. The modem will reply with the text of the first SMS in the inbox along with senders mobile number and date and time.
- To read the second SMS from the inbox send the command AT+CMGR=2 followed by rn. The modem will reply with the text of the second SMS in the inbox along with senders mobile number and date and time.
… and so on. The maximum number of SMS messages in the inbox depends on the SIMCARD you have put in the modem.
- To read all the SMS messages from the inbox send the command AT+CMGL=ALL followed by rn. The modem will reply with the text, senders number, timestamp of the all the messages in the inbox in one shot.
Sending SMS message from SIM900:
- To send SMS from SIM900 send the command AT+CMGS=9900243245 followed by /r/n and then the message text and then the ascii code of Ctrl^Z character which is 0x1A
ex: To send “Hello” to 9900243245 mobile number
AT+CMGS=9900243245 followed by rn
Ctrl^Z ascii code 0x1A followed by rn (Ascii code for n is 0x0A and Ascii code for r is 0x0D)
Deleting a SMS message from the Inbox:
- To delete the first message from the inbox send the command AT+CMGD=1 followed by rn. The modem will delete the first message in the inbox.
- To delete the second message from the inbox send the command AT+CMGD=2 followed by rn. The modem will delete the second message in the inbox.
… and so on. The maximum number of messages in the inbox depends on the SIMCARD you have put in the modem.
Calling to a number using SIM900:
- To call to a number send the command ATD followed by the mobile number and carriage return ,
To call the mobile number 9900243245 send the command as,
Hanging up a call in SIM900:
- To hang up a ringing call or a call in progress send the command ATH; followed by carriage return
Recieving a call in SIM900:
- To receive a ringing call, Send the command ATA; followed by carriage return
Finding the number of the incoming call in SIM900:
- To get the number of the incoming call you need to enable the Caller Line Identification in SIM900.
- To enable the incoming caller line identification issue the command AT+CLIP=1 followed by carriage return
Once you issue this command, any incoming call will be notified in the following format,
Here +9916259273 is the number of the incoming call.
Click on below Image to Watch the video for Live demonstration of the above commands:
2 thoughts on “SIM900 SMS and Call Commands”
Sir i am using gsm module m590 AT+CMGS=”880231xxxx” then output is > then after i type msg” hello world” but output is errors
You might need to send AT+CMGF=1 first and then AT+CMGS=”xxxx”; and type text after > and send 0x1A character as i had shown in video