Problem in receivine the call aastra 480i Need HELP


I started configuring the aastra 480i phone using th web-gui screen instead of going through tftp and i have come across the following problem.

My settings are like this.

I have asterisk 1.4.4. installed on linux pc and one sjphone also installed on the same pc.
i tried configuring an aastra 480i phone using the web-gui
In the asterisk server when i type “sip show peers” i get the aastra phone "unspecified " host.
But when i make a call from my aastra phone to the soft sjphone the other phone is ready to receive and the call gets established. but the same when it is tried from the soft phone to aastra i just get a beep sound and it shows a missed call.
I am not getting any ring tone on the aastra phone when the call is made it immediately goes to the missed call .list…
I would really appreciate if anyone help me in solving this issue. i
Thanks in advance