[Asterisk-Users] Interconnect with Mitel PBX

[Andrew C. Brown]

Chris Mason (Lists) wrote:
> I have a small government department that wants me to implement a
> Asterisk installation, however, they connect to the Government PBX, a
> Mitel SX200, and want to keep the ability to do that. I know there is no
> chance to connect the digital extension lines, but would it be possible
> to have the pbx admins send analogue extensions over and have those
> lines interface through an FXO interface? Or what other way could it work?
> 

For calls headed to the Mitel, the Asterisk FXO shouldn't be able to
tell the difference between a PSTN trunk and a PBX analogue extension
being used like a trunk. So that should work just fine. Then using
extensions.conf you can choose how to map the Mitel dial plan into your
Asterisk dial plan... whether your users dial a certain prefix followed
by the desired Mitel extension or what.

Incoming calls would also work the same as pstn trunks which means the
Mitel admin will have to provide you an analog extension for every point
at your site they want to reach directly via their dial plan. If you are
sending them all to auto attendent, that amounts to only one.

How are they currently connected to the Mitel? If they have their own
copper and want to get clever, you could see about putting a PRI trunk
card(s) into the Mitel and a matching one into the Asterisk. By
connecting the two using PRI protocol you would first of all now have a
digital connection end to end, but along with that, caller id
information and call line id which would allow you to map any or all of
your users into the Mitel's dialplan (DID) without wasting copper.

The latter approach, while higher quality (D/A-A/D only happens once),
more dynamically flexible, and definitely more cool, is certainly far
more complex to set up on the Mitel side (you'd get to know the Mitel
admin very well). On the Asterisk side it may actually be easier since
it obviates the need for a channel bank, and configuring the channels is
no harder than it is with Zap FXOs.

It is perhaps also the bigger capital expense since PRI cards are
relatively expensive. But depending on how many wasted trunks this frees
up, you could still come out ahead.

With the way government works, I'm guessing PRI won't be an option for
you since it means sharing the expenses between two different
organizations, something accounts just love to go nuts over.

With the FXO approach be sure to read up on the hardware offerings on
this list. The single line jobs aren't known for being the must robust
in call quality.

If you pull this off, please be sure to add your experience to the Wiki
under Mitel. I'm looking at doing something like it in the future with
the Mitel dealer I partner with.

Andrew