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Viewing 7 posts - 1 through 7 (of 7 total)
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  • #24704
    David Spalding


    I have a problem and I need a solution. I have two PBX’s in two different towns. Say, A and B. I need to tie together both PBX’s in such a way as to allow people in town A to be able to talk to people in town B. This has to be done with out going through the local PSTN. The towns are approximately 2 miles apart.
    I would be happy to clarify and
    I look forward to suggestions.



    Do you have any other infrastructure between the towns eg fibre or a radio link?

    Do your PBX’s have networking capabilities?

    Do you have line of site between your 2 locations?

    if you want to discuss it further , fax me your email address

    Don McK
    ++61 8 8110 5100

    Nuriel G.

    You need 2 FXO gateways to connect to your PBX and than you’ll need the services of a gatekeeper to route the calls. gateways will be connected to dsl lines.

    David Spalding

    Hello DCMK:

    There are in all, five towns all strung out along a highway. Point to point is about ten miles. We do not have line of sight between all the towns. Some do, others don’t. We have not decided on what exact brand and model of PBX we intend to use. We are however very strongly considering a PC based PBX. This should give us lots of flexibility. Unfortunately there is no existing adequate infrastructure between the towns. The closest thing is aerial electrical power lines for 240v a/c and another for 33kv a/c. We are going to have to put telecom cabling in ourselves. One of the options that we had thought of was to put in coaxial transmission grade cable. Or at worst, coaxial double or quad sheilded RG6 or RG11 cable, with adequate amplification along the way. The other option would be dual strand single mode fiber depending on the cost). DMCK, what country are you in and what is the correct country code? Thanks.

    Hello Nuriel G.:

    Thanks for the reply. Considering that there are five towns in all. (Which you were not initially aware of) All of which are strung out along a highway in a linear fashion. And also considering that there is no internet service there. And assuming that we are able to put in our cabling. how then would it affect the possibility of using the Gateway and Gatekeeper solution that you suggested. Would every PBX have to connect directly to the Gatekeeper? Or could they be daisy chained. Also I presume for this Gateway/Gatekeeper)approach to work we would essentially have to set up our own WAN/Intranet, which we do not have a problem with. however would that involve th addition of a router/s. If so how exactly (physical topology) would the router interface with the Gatways and the GateKeeper? I look forward to hearing from you.


    Coaxial cable next to power lines, specially high volatge power lines is not a good idea. Not only will be very hard to keep the noise from filtering into the coaxial, the voltage that will ‘radiate” from the power line into the coaxial needs to be patch to ground every few poles to be sure that voltage does not end up on the equipment.

    Fiber should be the perfect medium if you could afford it. Up to mile or mile and a half, you could use multi mode fiber, very simple to conectorize and handle. Over that distance you will need single mode fiber and muxing equipment.

    If all what you want to transport is voice for several PBX ‘s, you could get your hands on very cheap muxes taht will transport E1 ‘s or T1 ‘s for the voice.
    If the PBX only handle DS0 ‘s, that means 2 wire lines, you could still get a channel bank for each town and do drop and insert,using a channel bank to transmite and receive on each direction over the fiber link.

    Or if you do not have the PBX ‘s yet, you will be better getting a PBX that will handle fiber optic .
    There are several on the market that do that right now, and price is not as high as used to be.
    This PBX ‘s have a central CPU unit, with all the brains, and remote cabinets, via fiber that are called expansions.
    The added benefit of that is that you get a uniform dialing plan, with everyone being able to talk to everyone on the system.
    If you need any aditional help, post your e-mail on the board and I will answer.


    I’m in Australia, country code 61 then state code 8, then number, 81105100

    or if your in Aust too, 08 8110 5100

    David Spalding

    Hello dmck & noname:

    Thnaks for the advice. As a matter of fact we do not have the pBX’s yet. We were looking at putting them together on a PC Platform using probably LINUX as the OS, Voicetronix, Dialogic or Brooktrout hardware and a good open source telecom application. We figured that this would help get the cost per port down as well as allow the use of any regular DTMF telephone and make maintainance easier. Above all is the cost per port and uniformity of hardware and firmware throughout the setup. We are looking at servicing about 200 customers at each town / PBX. Building the PBX’s will also allow us the flexibility to mix and match interfaces. Your concerns about the EMI on the coax will be seriously considered. If only we could find some cheap fiber.

    My email:

Viewing 7 posts - 1 through 7 (of 7 total)
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