If you are having problems with your SIM900 you can call us at
If you wish to try and fix the problem yourself, the user manual may be useful, and the following troubleshooting guide may be helpful too.
1) Can't send commands remotely over GPIB or
Click here to download programming examples for the SIM900 Series.
2) Installing the GPIB interface (opt. 01) in the field
Click here to download the installation procedure. You will need to call SRS at
If you are still having trouble your SIM900 Series Instrumentation, you will need to send the instrument(s) back to SRS for service. Click here to get an RMA number.