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[General] problem reciving SMS after sending SMS using sim900

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alzomor

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Dear Sir,

I am using Sim900 for sending and receiving SMS for new M2M home automation project

Here’s my settings

For initialization
AT\r\n
ATE0\r\n
AT+CMGF=1\r\n
AT+CNMI=2,1,0,0,0\r\n


And for receiving SMS I wait for new message indication conataining “+CMTI” and when receiving this I extract the messahe index from the “+CNMI”message and do the following to read the message
"AT+CMGR=index,0\r\n"

Then delete the message using
"AT+CMGD=index,0\r"

And for sending a message is use
"AT+CMGS= \" SIMCardNumber \" \r\n
And then wait for receiving “>” and send message and "\x1a"

I can receive several messages as I didn’t send any but after sending a message I didn’t get the “+CMTI” new message index from the module.
In order to receive more messages after sending a message I restart the module and do the initialization again.

is there any suggestions to overcome this problem

Regards
Hossam Alzomor
 

ponnus

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Hai,
Are you getting +CMGS response after sending message and are you able to send more than one message?

I think you have to send 0x1a, not "0x1a" to end the message.

Also, if you use AT+CNMI=2,2,0,0,0, Sim 900 will send the message directly to the device instantly on reception.

Hope this helps,
 

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