You can "switch" to the BT3900 stack,but don't do it unless you're having problems with the 3500 stack. Some things get better, and some get worse, so if it ain't broke... don't fix it.

The data icon. If it has an X, it's not on. (Not dormant, not active, NOT connected.)
If it has two arrows moving towards right and left it's trying to connect, but has not yet succeeded in connecting, logging in, getting an IP address.
If it has two solid arrows, then it is connected, although that won't show you if it's DORMANT or ACTIVE.

You can run fieldtrial.exe to see if the thingamagigie (slot? mode?) is 33 or 1. If it's 33 your data session is ACTIVE. 1 and it's dormant. 0 means something but you'll have to ask Dan -- I don't know

Ehud