Hi Avi
Here is a basic config that should work. The first thing you need to tell the Nortel engineer is that the PBX needs to do network side, the gateway can only do network side for switch types Ni and Qsig. The other thing you may need to consider is whether or not you are passing name display info, usually for this the pbx is set up as SL1 network and you would add the command "isdn flip-chan flag" to the d-channel config on the gateway.
isdn switch-type primary-dms100
!
controller T1 1/0
framing esf
linecode b8zs
pri-group timeslots 1-24
!
interface Serial1/0:23
no ip address
isdn switch-type primary-dms100
isdn incoming-voice voice
no cdp enable
!
dial-peer voice 9 pots
incoming called .
destination-pattern 9
progress_ind alert enable 8
progress_ind progress enable 8
progress_ind connect enable 8
direct-inward-dial
port 1/0:23
Sam