remote office and pbx

Posted on 2012-08-28
Last Modified: 2012-08-31
We have an Avaya IP Office 500 pbx in our main office that is setup to use both digital and voip phones. We also have a remote office (no pbx) with a vpn connection to our main office. I have two questions:

1. What is the benefit of installing a pbx in the remote office? The requirement is to have users to be able to call locally using their new ip phones and to be able to call the main office by dialing 4 digits. The same goes for calling from the main office, the requirement is to be able to call a local number in the remote area site from the main site as well as a 4 digit ext to the employee.
So how does it technically work? If I'm in the main office and dial a local number at the remote site, it goes through the vpn connection and the pbx there would pass it off as a local call through their pbx to a local line (analog or T1)to the destination number locally, but if I call a user there using the 4 digit extension their pbx just passes it to their externsion in the office. And the same would be from the reverse of them calling from there to here, correct?

2. Instead of installing a pbx in the remote location, is there anyway to accomplish this requirement? Perhaps there is software available from the local ISP that can accomplish this or some other software or soultion which would not require a pbx?

Question by:tolinrome
    LVL 2

    Expert Comment

    I'm going to jump on this to start out suggestions with the following-

    Trixbox as your PBX with service from your favorite VOIP. I recommend Virtual Tone. They have amazing pricing plans and can build in whatever you need.

    I would then set up two TZ215 's on either side as your VPN.

    Configure your phones to be on IP range and statically assign each phone inside that range you made a reservation for on your TZ215's. Connect the VPN's together in Bridge mode.

    Inside your PBX you would have to configure each phone that you assigned statically to have that "local" number of where it is. You would also have to pay for the ability to have multiple local dial out numbers. I would suggest one for each user that needs an independent out. Each phone would be able to call one another as well as call out locally.

    Is this what you were looking for?
    LVL 7

    Author Comment

    thanks Ben, I'm going to have to research all that, but for starters, did it make sense of what I wrote on #1 - is that how the purpose of the pbx would work and route calls? I need to make sure before I start going deeper.
    Were looking for what I mentioned in point#1 - We have to be able to call locally from either site to the other site and of course call each other. I just wasnt sure how the pbx handled that technically. The pbx takes the call from the remote site and see's that it's a local number there and then routes it out another (analog or T1) line, but if the number is for someone in the office (4 digit ext) then the pbx just forwards the call to the ext. So obviously both calls (whether a local number dialed from a remote site or a 4 digit ext) goes through the vpn and the pbx would decide if the number is for the office or a local number in the area and forward the call to that appropriate destination?

    if I go with what you suggested (Tribox\Virtual Tone) then would the IP office we have become obsolete? Are these apps widely supported?
    LVL 2

    Expert Comment

    Hi Again!
    Yes it makes sense what you are saying.

    Think of the IP phone as a Computer. It has firmware, memory and an IP address. You configure all of this into the setup and then flash it to the phone. (provisioning)

    You can call locally to any number you have setup with that service. You (provision) setup that setting in the phone/virual pbx and it configure the phone upon reboot. Usually with a Polycom Soundpoint 450 it updates upon reboot.

    I love the Trixbox for its wide range of availability. I have not used your current PBX but have been reading up on it. It's an interesting unit. I suggest to most everyone to go a Virtual PBX solution because if you need more phones you just configure the virtual side and its done. Plus you can daisy off of it to a computer and you have a seamless looking work area.

    These apps are widely supported. There is a plug-in for the desktop that gives you a console view which is pretty user freindly. Other then Virtual Tone (I have used them in the past for multiple different jobs and love their customer service) I would recommend the makers of Trixbox being- Fonality.

    Usually with any company you are looking at using as a preferred vendor that can help you setup the VPN and software and provision all your phones. If not you can always ask us at Experts Exchange and we can walk you through it.

    LVL 15

    Accepted Solution


         First off do NOT follow Ben's advice.  Trixbox CE is unsupported and has been for awhile.  There are a number of other ISO based distributions that are supported and will be much more stable.  With regards to Virtual Tone, never heard of them.  

        Second to answer your question more directly.  The issue of placing a box (IPBX) locally usually has to do with the features you are looking for and the bandwidth between the facilities.  If all you have is phones at the second facility then any call between extensions in building two, between building one and two, between building two and Voice mail, and between building two and rest of the world will use up VPN bandwidth between the two facilities.  

        Additionally, when the network connection (VPN) is not available all of the IP handsets will also be unusable.  By placing a box and doing some least cost routing in the box, you can have local extension to extension service, and some form of alternate connection such as a couple of PSTN lines or a naked DSL with a secondary provider.

         Four digit dialing and other features with two boxes is usually just a matter of planning and dial plan coding.

    LVL 2

    Expert Comment

    Hi Phone buff
    Trixbox CE is unsupported, your absolutely right.

    Trixbox Pro is and has 24/7 support.

    Also was referring to this Trixbox not a server install or VM install...but you could do that still with the Pro side.

    Yes, when the VPN is down your phones will be down. That is why I suggested the TZ215's on either side. **edited *** For the ability to have 2 new devices and same model and specs with a highly backed product.

    Thanks for jumping and helping PhoneBuff, I always appreciate more insight on topics.  =)
    LVL 15

    Expert Comment

    Sorry Ben -- Your Posting ID: 38341903 arrived while I was typing mine and I did not see your qualification of the Trixbox product.  

    I started out many years ago Green, but all of those boxes have long since been replaced.  An I don't recommend the Cloud to most people getting started with SIP to many extra out of there control variables.

    Your Welcome...
    LVL 17

    Assisted Solution

    But if the company has already invested in the Avaya IP Office and if it is current release software, it is not necessary to replace it with something entirely different and new just to get the features needed.  Replacing the Avaya system will require purchasing different phones and other added expenses.  If you want local office survivability but four-digit dialing between offices over a VPN connection it can be done with the IP Office.  

    Not that any of the suggeestions were bad, just that it is not the only course of action.

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