SIM900 AT+CGATT=1 returns ERROR sometimes and keep giving continiously

[jpksampath]

Hi experts,
I'm using SIM900 with Atmega64 for communication with a server over GPRS.
My code was working fine for some time.
But I changed the SIM card and run the code.

When attaching GPRS, (AT+CGATT=1) some times it returns error. sometimes it works fine. But when the ERROR started it remains giving "ERROR" even if I restart the modem, program or any thing.
After reprogram the micro controller sometimes it works fine.
And when I enter same commands to SIM900 using serial port of computer(from microIDE) it worked fine every time
I can't figure it out.
Pls help.
Thanks in advance
BR
SAM

 

[sa4250mnpo70]

Can you provide the circuit diagram of your SIM900 and ATmega connection...
also the full code that you are using...??

 

[jpksampath]

HI sa4250mnpo70,
I figured this issue. It was due to the delay after setting apn settings was not enough. Now it is OK.
Any way Thanks for your concern.
BR
SAM

 

[kunal123]

HI,
I'm using SIM300 with Arduino uno for data transfer between arduino & remote server using gprs, i tried at commands for gprs on hyperterminal as follows, but enable to establish connction between gpars module & remote server.
<<at+cipshut
SHUT OK

at+cgdcont=1,"IP","airtelgprs"
ERROR

OK
at+cdnscfg="202.56.230.5","202.56.240.5"
OK

at+cstt="airtelgprs"
OK

at+cgatt=1
OK

at+ciicr?
OK

at+cifsr?
OK

at+cipstatus
OK

STATE: IP START

at+ciphead=1
OK

at+cdnsorip=1
OK

at+cipstart="TCP","www.gotcubed.com","2020"
ERROR

at+cgact?
+CGACT: 1,0

OK

at+cgact=1
+CME ERROR: 596

thanks