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SIM 900 problem sent to sms

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83stef

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i have a probleme with the SIM900 :

SIMCOM_Ltd
SIM900B
REV : 1137B05SIM900B32_ST

impossible to send a SMS with AT command ?????
my séquence AT:

ATZ
OK

AT+CMGF=1
OK

AT+CMGS = "+33679412827"
>my message
OK

but never no SMS received ????? :-x
if I try with a chip SIM300 the same sequence AT is OK -> SMS sms received

I'm going crazy??
thanks stef
 

"ok" is the answer of modem after "CTRL+Z"
 

please free the SIM memory as if it is full then it cannot send messages tooo.....

check tx and rx connection in serial cable and modem once again
 

thanks ckshivaram i'm checking...

---------- Post added at 20:49 ---------- Previous post was at 20:04 ----------

i have nothing found :|
I changed the sim card, impossible to send an SMS...
-> the modem is OK for receiving the SMS (command AT+CMGR )
 

its visible problem i feel in 2 fold ways...

modem gets message when sent from mobile as the max232 rx is working fine on modem and controller side. and cable is correct.

when modem should transmit then, AS modem it is sending so problem happens in the MAX232 of modem or pin 2 of cable on modem side ..

please do the following and let me know....

1. serial cable loop back test.. short tx and rx and typr to see you get same data on terminal, if not the there is some problem in cable.....
2. if works fine then short tx and rx and do the same test in power ON condition.. make sure you dont short it for a longer time....

please reply to me after doing this..
 

dear ckshivaram...I slept a bit and try again ...
it's ok ! probleme my cable rx.... thanks you very much stef
 

I too have the same problem

My program sequence
AT+CPIN?
AT+COPS?
AT+CMGF=1
AT+CMSS=1 (as the msg to be sent is saved in this particular location)

With SIM 300 the AT commands works fine and msg is sent but when the same commands are used for SIM900B

it sends back "ERROR"
Please let me know what could be the problem
 

Thank you for replying..

I have tried all but the problem is still the same.
SIM900B replies properly for all the commands but for
AT+CMSS=1 it gives ERROR as output
 

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