Nokia 7650 modem - disconnecting after a while

Hi guyz, I would be really happy if somebody helps me with this:
I have a USB IRDA dongle and I am trying to connect to internet through that with my nokia 7650.It will make a connection (GPRS), but after 1 minute it will disconect me.I am using windows xp, the settings on irda are -
- min turnaround time - 5ms
- infra type - sigmatel 4000
- speed - 115200

Why da hell it is not working.....

normal infra red will shut down automatically, i onli noe that pairing wif pc suite will keep the infra red going till pc suite is closed.