I have T-Mobile. When I try to establish a GPRS connection using the TCP/IPstack, the modem doesn't connect. It seems like the modem gets reset.

- Check the firmware version: 'AT+CGMR'.
- Version 640b had a bug that caused the modem to reset when using a non-authenticated account. Authenticated accounts such as AT&T and Cingular work. Firmware version 641a and later fixes this issue.
- You will have to send the modem in for a firmware upgrade. Send it to the attention of Repairs and include a letter stating the problem and that you need 641a or later firmware.