After some time our TC65 GPRS terminal shuts down without giving any kind of message or error. We don't get the ^SHUTDOWN line neither a temperature or voltage warning. After some research in internet we discovered that is a problem that other people have suffer but in the few threads that can be found regarding this hardware you will not found any long term solution (Even a lot of this blog entries are already locked).
We were struggling for a long time but finally we have found a common pattern in the deployment actions of the midlet in the TC65 that could be propitiating this behavior.
First of all, we weren't using the last emulator (provided in our case by CINTERION), we were using a legacy emulator of SIEMENS. In the same way the firmware was out of date, we were working with 2.0 firmware instead 3.0.
Using the new emulator and the new firmware the problem appear a lot less, but wasn't a complete solution, The real solution is making the deployments without using the netbeans RUN command.
We are not sure why deploying the midlet using netbeans makes the midlet stop working after some random time, this is a really strange behavior but after deploying manually copy pasting the jar and jad files the terminal never stops working.
Once again we can't give a real explanation of why this error occurs but for the moment this is working for us and let us keep forward our development.