I am using the above set up as Standard PCMCIA Card Modem as I need to develop an application using standard AT+ commands.

To send an SMS I use:-


wait for OK


wait for >

The Message text <CTRL-Z>

If I do this command sequence from a terminal emulator then it works fine and I get the correct response.

The same thing happens when I try the sequence (from C#) in step through mode, where there is a debugger pause between the GMGS command and the sending of the text.

But if I try to run this outside the debugger I get +CMS ERROR 310
which apparently means no SIM in the phone and makes no sense at all. If I now stick a breakpoint between the last two statements then again the message is sent and all is well.

I have tried putting a Sleep(x) pause between the last two statements with values varying between 10 and 1000 ms. to no avail.

Any idea what the problem could be?

Bob Morris