XP Remote Desktop, Idle Timeout

>I am using a Windows 2000 SP3 machine at work to
>connected to my home computer (Windows XP SP1) via the
>Remote Desktop function.
>
>Occasionally, when I get up and leave my computer for
>more than 30 minutes or so, I'll come back and pull up
>the remote desktop screen and it will be completely
>frozen, and within a minute or so, it will disconnect. I
>only see this behavior when I'm idle, however. I've never
>had it lockup or disconnect me while I'm sitting right in
>front of it. Is there a setting somewhere in XP that's
>disconnecting the idle session? I've poked around the
>Local Security Policies and didn't see anything there.
>
>Any help would be greatly appreciated.
>
>TIA.
>
>Adam McKee