The cable for the SMS application worked well. Actually, so did the application, but I am getting ahead of myself here. I got much of the programming outsourced. Frankly I could have done the work without issue, but right now I really do not have the time. Step one was to get the modem working with my PC. I have a heap of SonyEricsson modems removed from old tracking units. They are missing the RF modules, but they are fairly cheap. Power cables for these units are a pain since they use RJ12 like telephones. Then the serial cable needed to be made up too – not too hard; I used a VGA cable for one end and put a DB9 socket on the other.

This would have worked first go except for two things. Actually three things. Firstly, I forgot to plug the power into the modem. Then I forgot to plug the serial cable into the PC. And lastly the GSM module in the phone was faulty. Replacing it was easy, and it now all works. Or the hardware works.

I tried the software out, and it worked first go. Reads out the serial number of the SIM, Signal Level, model of the modem amongst other things. What I really like is the test application that comes with the work I got done. To send a text message all you need to do is
If wrSMS.Open Then
wrSMS.Add("0412929634", "This is a test of SMS Sending")
wrSMS.Close()
End If

Receiving is almost as simple…
If rdSMS.Open Then
TB.Lines() = rdSMS.Retrieve
rdSMS.Close()
End If

Now all I need to do is write the tracking application to go with this.