Unlike Cisco which have integrated ATA's management, for Nortel it's define as a remote site. IP Peer networking have to be implemented:
1- Create Virtual DCH
2- Create Virtual Route
3- Create H323 trunk members
4- Create RLI
5- Create DSC
Then on SigServ, you have to configure NRS part:
Your SS have to be preloaded with a co-resident gatekeeper, done during software installation. Then define the address of your NRS in element manager. It's normally then same address of your SS TLAN. Access NRS with allocated tab.
1- Create Domain name (might be anything, unless you don't decided to use SIP)
2- Create Level 1 domain
3- Create Level 0 domain
4- Create Gateway endpoint. It can be RAS h323 endpoint or fix IP@. In 1st case, give then H323 name define in your ATA box.
5- Save and apply.
Then in active view, you may see your box registered in Gateway endpoint tab.
6- Create routing entry, which in the DSC of your PBX and give direction of your ATA box.
I don't know your ATA box, but it's all the same kind of stuff, which required some basic definition.