When I started to work with Asterisk, my goal was to eliminate the Nortel switches, call pilot and their ACD tool Symposium. I never attempted to put Asterisk in place of just the Call Pilot portion. I don’t know much about a Norstar system, as I had been working with Meridian hardware, so perhaps what I am about to say will not translate to your situation.
Using a PRI as a gateway between the Meridian and the Asterisk systems, I could conceive of a way to get some dialplan code in place that could work, though I have never tried it.
Asterisk also has the smdi interface, but I have no idea if any Nortel boxes actually support that interface. I do remember the old Meridian Mail did use a serial link to the switch for communication, but I never really looked at the details. I really do not know if Call pilot has the same, but I think it is a network based interconnect instead of RS-232.
Time for a sales type pitch, sorta.
Instead of simply replacing Call Pilot, perhaps you could consider replacing the system. The truth is, Nortel is dead. I will not go into the details of why I wanted to get rid of them before they went bankrupt and before Aviya bough the remnants. But the bankruptcy sure help sell my case for switching. The flexibility of the Asterisk has allowed my to do things, that even if possible with Nortel, would have been too costly to implement. (I completely replaced 4 PBXs for the cost of a Nortel VoIP gateway!)
What I did in order to reduce the cost of replacing all the endpoints was bought several ‘appliances’ that emulate, to the endpoint, proprietary switches such as Nortel and NorStar. It then presents those endpoints to Asterisk as SIP clients. This allows me to ‘re-purpose’ the existing endpoints. Another advantage is that I did not have to wire Cat-5 wherever there is a phone (yes, there are still more phones than computers in our company). I literally pulled the tail off the Nortel switch and plugged it into the appliance.
Now I simply replace Nortel endpoints with SIP endpoints when time and money permit.