I'm using my N900 with T-Mobile USA, only get 3.5G when I'm using data. When it's voice only, I get 3g.

I'm actually experiencing a weird issue with my N900. If I don't set my phone to 3G only, when I hit 2.5G or 2G, while I'm using data, the phone won't reconnect on edge. Basically data doesn't work what so ever when voice is on 2G or 2.5G. I know for sure it's not the sim or network's issue because I'm using the same card on my old phone and I don't have any issue with edge.