Integrating Asterisk With Nortel PBX

I have an interesting problem that I’m hoping some of you who have more experience will be able to help me out with.

Management has made the decision for various reasons that we want to start moving toward an Asterisk based system. However, in an effort to make things complicated for me, they have decided that they want to make this a transition wherein we are only replacing a few of our Nortel phones at a time.

The PBX is a Nortel Meridian, and the phones used with it are Nortel T7208.

The way I see it, there are two possible options for programming this system. Neither of which I currently know how to do, but I would like clarification on the best way to go about transitioning to an Asterisk based system in a way that satisfies my bosses. We have approximately 45 users.

Option A)

Find a way to hook the T2708 phones directly into an asterisk box. I think this if possible, this is likely the easiest thing to do. Is it possible to program these phones to act like a regular analogue phone? And if so, would it make sense to buy ~45 FXS modules or ATAs and plug the phones into them.

Option B)

Leave the Nortel PBX in place, but place Asterisk in between it and the telco. Run x FXS modules from the Nortel box into Asterisk. The problem with this situation is that I have to find a way to make it easy for users of the Nortel system to call users of the Asterisk system - as well as the reverse. Can anyone let me know if this can be done, and if so, how I should go about doing it?

Thanks to anyone for any insight that you’re able to give.—Portico TVA can act as a device that will convert all your digital phones (and keep their digital features, multiline calling, hold transfer, Message Waiting Indicator).

The 12 or 24 port Portico Telephone VoIP Adapter- (TVA) will make it easy and cost effective to take those Nortel T7208s into VoIP enable phones. It is as easy as taking the amphenol connector off the back of the Nortel PBX (for each block of 24 phones) and then connecting to the TVA and putting in the AoR and other SIP account info for each DID etc. As long as the TVA has IP connectivity to the Asterisk (remote or local) then the TVA can solve you main issue and possible save time and money in your implementation.

If you have any questions I will be at Astricon in AZ 9/25 to 9/28 at the Citel booth.

Allan Floyd
Sr. Engineer- VoIP Design

I actually just did such a migration for a customer. Problem with this kind of migrations is that adding something to the Nortel box costs a lot of money.

I assume you have a isdn connection on the Nortel. If you have you can place the Asterisk box in front of the Nortel.

outside world <-> asterisk <-> nortel

This is the checklist:

inbound call to asterisk phone
inbound call to nortel phone
outbound call from asterisk phone
outbound call from nortel phone
transfer call from nortel phone to nortel phone
transfer call from asterisk phone to asterisk phone
transfer call from nortel phone to asterisk phone
transfer call from asterisk phone to nortel phone
transfer call from nortel phone to external number
transfer call from asterisk phone to external number

This should all work

You have to add some clever dialplan logic to the Asterisk box to make sure that an incoming number of an Asterisk phone is routed to this phone and an incoming number to a Nortel phone is routed over the internal isdn trunk to the nortel box.

On the Nortel box you have to forward the calls, over the internal isdn trunk, to the asterisk box and let asterisk handle it from there. If you can add a prefix, f.i. 4 to the Nortel box, so all numbers starting with a 4 are routed over the internal isdn trunk you just have to forward number 3456 to 443456 (something like *21443456# on the Nortel phone) and add 43456 (the prefix is stripped from the number by the Nortel box) as an incoming line of the internal isdn trunk and route the call to number 3456.

Using ScopServ ( will make you live much more easier while implementing this kind of solution.

Thank you both for your replies! Both seem like good avenues to explore, so I’ll do some more research and come back here.