GPRS Modem Disconnects/Stalls

[Singh_R]

I have written some software that communicates with a GPRS modem that sends/receives smses. Software has been running for over a year at quite a few different sites. The main issue that i am receiving is that the PC loses communication with the GPRS modem after a while (no specific timeframe).
I have tried moving it to several PC's but no luck.
We have tried it on Windows Server, Windows XP, Windows Vista - still no luck (default OS is XP).
Initially we were using the vodacom 3g modem (Huwai E220). Then changed to the iTegno modem. Now I have placed my personal test modem, Wavecom modem (which has an independant power source) at the clients site and still encounter this problem.
Some clients run for hours with no issues, and then suddenly it stops working. we have to close the software or unplug and re-connect the modem and it starts working again.

The software has been written in VB6 using AT Commands to communicate with the modem via a MSCOMM control.

Thanks in advance for any help.

 

[Other Pineapple Smurf]

Look at SMSTOOLS and see how they implemented the AT commands. You need to send regular reset commands. I wrote my app for my wife and had to constantly power cycle the modem.

I settled on SMSTOOLS as it just works. Its now been a year and never an issue, not once. We even deployed SMSTOOLS on our production servers.

BTW: My uses an E220