Oddly enough, this phone is a replacement that we got a couple years back because the first one was DOA, so who knows the history of this one before we owned it!?
I'll give your link another look and see if any of those keypresses will spark some activity, but it would seem to me like something is broken inside as it should at least be sending out some network traffic when it turns on (DHCP requests, etc). That is, unless there's a way to have the firmware disable all network traffic?
thanks,
Mike