setting up incoming data connections via 7650's modem.

I am dialling my companies RAS server via my computers modem.Server is comparing my username and calling back.So i dont pay anything.
I tried this process via my 7650's modem.RAS server asked me for the number that will be used for callback.I gave my mobile number.But after all my phone started ringing like someone is calling me normally.
How can i tell "this is a data calling" to my phone?
What must i do for "setting up incoming connections" via my 7650's modem?
:confused: