Inactivity Time-out

Hi all,My wireless phone from Tata indicom connects to the web very quickly. Unfortunately the reverse does not seem true. Oftentimes, My system tray shows a cute red X mark on the internet connection icon ( the two tiny blue green squares), which is supposed to mean that i have been disconnected. However, the phone still remains "off the hook" and shows the connection as live. Well, this never happened with my good old dialup modem.. It would always "click"- out when the software disconnected. The Tata indicom authorities have warned me to disconnect power after my session ( or i end up paying 40p/min for time i didn't use ) This includes turning off the battery switch hidden deep below in the belly of the phone, and of course the mains adapter too. This needs to be done even after i switch off my pc after my session 🙁 . My question is this:Is this plain shortsighted hardware or is it something that can be detected at the server end as a "long period of inactivity" through some polling and time-out mechanism leading to automatic discontinuation of the session?