As per our conversation, we need our OpenAT code reviewed and fixed.
Here are the problems needs to be fixed:
* GPRS connection can not be established after a certain time period. This situation happens between 1 week to 1 month.
* If the device stays in a place where GSM/GPRS connection not available around 3 days, we can not access device anymore both using com port and SMS commands which we designed in our application. We can restore device by powering off and then on unit.
* The device can not send messages to server after 1 week later even it shows that GPRS connection is established and a valid IP address is assigned to device.