SIM800C not working with Vodafone

I have designed a circuit using the SIM800C and tested it throughly using airtel SIM card. i am able send messages,call and log GPRS data using the modules.
The problem is with Vodafone SIM card.I am using a prepaid card and have tried with older and newer cards but SIM800C does not register.It is not able to detect the vodafone network.I have tried to change the DATA formats and everything but same result.There is no power issue since i am using a 4 Amp power supply and it working withe AIrtel .
Can anybody suggest any ideas i am at my wits end with this problem,

This is something strange and new. But lets try the following troubleshooting

  1. Did you see if other phones have a proper coverage to the vodafone? No? Try keeping the gsm module near the window with the external Antenna attached.

  2. is the module even reading the simcard? Use the command to check AT+CPIN?

  3. You even mentioned you tried the GPRS on airtel, but didn’t work on vodafone, Did you change the Apn to portalnmms ?

These are very basic things but see if it helps you.

Parth Temkar

Hi Parth
Thank you for your reply. I have solved the problem to some extend.The vodafone Sim card now gets activated in 4G LTE mode only.So I need to insert the SIM in a phone and then manually change the setting to 2G .Later when i insert the SIM it is detected and able to send the data.I got this information from an EDA board message.Hope this helps any other persons.

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A friend of mine worked for a large mobile phone company. I asked him why I had a problem connecting a new SIM from iD (Carphonewarehouse) he explained that certain mobile networks may not be work on the SIM800. My original tests worked on Virgin without any problem so I cancelled the iD account and bought a new Virgin SIM and it all worked perfectly.

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We have developed a customize board for GSM module using SIM800 IC. When the board was tested with the sim card of Reliance company then it was not detected but when I used the sim card of Idea company then it gets detected and all the AT commands runs using the module. Why only idea company SIM card gets detected and other Sim card are not? The error occured at AT+CREG? command which is AT command for network registration. For working idea sim it shows +creg:0,1 and for reliance it shows +creg:0,5.