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Integrating current PBX with new Cisco VOIP implementation

We've been looking around for a while at upgrading from our old PBX and moving to a VOIP system.  We have several offices spread across the country, and just looking at toll free routing, and savings in long distance along with having a more feature rich phone system makes us lean towards the VOIP solution.  We've been looking hard at doing Cisco, but wanted to get some more information.  We're being told with an Avaya system we could bridge our old PBX systems at our branch offices into the VOIP system as a way to phase in our implementation and wanted to know if Cisco offered the same kind of system.  I'm looking into it to flesh out the idea and have it as a second option if we can't get the full implementation approved, but I'm leaning towards the concept that it would be better to just upgrade everything.  Someone tell me if I'm crazy and bridging an existing old style PBX into a modern VOIP system works like candy and roses.


Re: Integrating current PBX with new Cisco VOIP implementation

I don't know what type of PBX you currently have; however, pretty much every VoIP migration I've been involved with has entailed configuring trunks of some type on a Cisco voice GW integrated with CUCM over to the legacy PBX.  For example,:

Customer has old Avaya PBX and can support 4 trunks to the Cisco solution during the "migration".  So, we provision 4 QSIG trunks and do andem routing as user migrate over to Cisco.  At some point during the migration, you swing existing PRI's (or new in some cases) over to Cisco and it becomes the primary PBX for the company.  When everything is off the Avaya, the tandem trunks can be removed and you say "Bye, bye old Avaya".

So, yes - it is possible to do this.  There are dependencies based on what type of PBX you currently have, hardware (can you support anymore trunks), etc...but yes, pretty standard procedure.

Hope that helps man.  You're in the right place for good information.


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New Member

Re: Integrating current PBX with new Cisco VOIP implementation

Right, the implementation is probably going to be phased in like that.  However, I'm talking about having a situation like this:

Main office full VOIP system, new phones.

Remote office 1, NEC system with NEC phones.

Remote office 2, Norstar system with phones.

Remote office 3, Avaya system with Avaya phones.

Remote office 4, Nuvox system with phones.

Now, my initial gut reaction is that I want to have the full VOIP implementation in my main office and I want to have CME running on routers at the remote offices that ties back to the main system running at my corporate office.  Someone's talking to my boss about doing the VOIP system at Corporate, but leaving the current phone systems in place in the remote offices but somehow (through a bridge of some kind would be my guess) bringing them into the VOIP system back at corporate so we could dial an extension from Corporate that goes out to the remote offices.  The reasoning being that we save money because we don't buy phones and routers for the outer offices.  Now, I'm not sure how well such a system works, whether it would be able to play nicely and allow us to dial extensions from all the remote offices and have them work together across the network.  I don't know if such a system would give us lowest cost call routing.  Those are the kinds of questions I'd have to look at, and I guess that should really be what I'm asking.  1) Does a Cisco VOIP implementation allow us to leave the current phone systems at the remote offices but still have them tie into the VOIP system.  2) Anyone have an idea of how well it works and what features we may miss out on.

For me, I don't like the idea of leaving all these disparate phone systems out at remote offices and trying to shoehorn them into the VOIP plan we've been developing.  I would think there'd be definite disadvantages and you'd lose a lot of the functionality you gain by going VOIP.  Keep in mind that these phone systems aren't in any way integrated today.  However, due dilligence requires I look into the option, and if it is a viable option that has some benefits I'm perfectly willing to reverse my position if there's some compelling argument for keeping these old phone systems kicking.