Modem communications


I would be very grateful if someone would find a solution tho my problem.

I’m using serial port C on OP7210 Rabbit with RCM3200 core module to send SMS. I’m using my own program, not the modem library included with Dynamic C.

Most of time, everythings works fine. But sometimes, the serial port does not receives all the characters in the response. Modem works fine when connected to a PC.

Ground refferences of the power supply, the modem and board are all the same. I do not use CTS/RTS. So, I connected RTS and CTS lines together on the modem side, I made the same thing with DTR and DSR lines. I used a very low baudrate (2400).

Do you have an idea about what is the problem?

Thank in advance,

Stephane Lemelin.

That’s a difficult question with the limited info you’ve posted. You’re not even using standard libraries so who knows where the code could be going wrong. A shot in the dark would be to increase your incoming buffer size, assuming you’re using the RS232 serial library. Do this by defining CINBUFSIZE to a larger (2^N)-1 value. The default buffer size is 31, so if you haven’t defined this value, try 63 or 127.