Connecting PBX's

Discussion in 'VOIP' started by C, Jun 28, 2003.

  1. C

    C Guest


    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.

    C, Jun 28, 2003
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  2. Check out the Asterisk PBX: You can interface
    your existing PBXs using a normal telco trunk (FXO, E&M, or PRI
    depending on your needs) then Asterisk would make VoIP calls between
    your two PBXs.

    If you can the Line of Sight within that two miles you can use the
    Orinoco Wireless gear or you can buy wireless local loop T-1 gear, but
    that is dramatic overkill.

    If you do this right you could set it up for one fixed start up cost and
    absolutely no monthly fees.

    Isn't it cutting ma bell out of the equation a great thing?

    Jeremy McNamara
    Jeremy McNamara, Jun 28, 2003
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  3. C

    eMail2Me Guest

    Basically you can connect the output of any FXS device to the input (telco
    line) of a PBX. For the software part, depends on your FXS device, you can
    either use asterisks, opengk, etc. that has a support on it. For instance,
    if you still can buy an inexpensive VoIPBlaster FXS device, you can use
    fobbit software as well (
    eMail2Me, Jun 28, 2003
  4. C

    shope Guest

    You posted this is a Voip group - but no mention of any voip issues in the

    what you want to do is called lots of different things - tie line, least
    cost routing, call optimisation to name a few.

    with the 2 sites that close together i would check out non Voip solutions -
    bandwidth (either your own link based on fibre or microwave, or a leased
    circuit) should be pretty cheap - so the complexity and cost of converting
    to IP and back may not be justified.

    Also a reasonable PBX should come with support for analog or digital tie

    check with the PBX supplier for what their boxes can do - that should give
    you some suggestions on what to look at indetail.
    shope, Jun 28, 2003
  5. C

    RealWiild Guest

    Hi C

    I would agree with the others replies to you.
    You do not specify how many calls (1, 10, 24,30, 100) ? which PBXs ? if
    there is H.323 support in the PBXs ? If you have LAN/WAN connection between
    the sites ? If incoming calls from PSTN on one of the sites should be passed
    on to users on the other sites ?

    You need to provide a hole lot more details about the current setup, and
    what we have to work with.

    Cheers, Real
    RealWiild, Jun 28, 2003
  6. C

    C Guest

    Gentlemen: ( I presume)

    Thank you very much for your very helpful replies. I shall be responding
    directly to your replies. Most of the sugestions are very sound. I shall
    research on them further.

    To throw some more light on the problem. The application will be for a
    number of towns (5) in a West African nation. The setting is rural. The
    local telco cannot effectively serve these towns whcih are strung out in a
    linear fashion along a main road.The telco is located in the largest of
    these towns and serves that town with about one hundred lines. (Pop 46,000)
    the only other town served has a total of three lines. The other three towns
    are served by a radio link to one telephone each. A local call is about 0.50
    cents/min. There are always long waiting lines.

    Most of the communication will be between these five towns. The peak will be
    in the evenings, nights and on weekends. We still have not decided what type
    / model / make of PBX yet. The maximum number of extentions though will be
    around 200 for each pbx.

    For trunking cabling between the various pbx's, we had thought of using
    coaxial cabling. perhaps, RG6 with an appropriate mux of some sort.

    Has anyone evehad experience using this or similar types of coax for
    telephony purposes ? Thanks.

    C, Jun 30, 2003
  7. C

    Miguel Cruz Guest

    How far apart are the towns? Are we talking central Mali where there's no
    electricity grid and the tallest obstruction is the occasional termite
    mound, or southern Cote d'Ivoire where there are poles everywhere and the
    trees are lush and gigantic?

    I imagine that running coax is going to be an expensive and fragile
    proposition unless there are already poles that you are allowed to use. If
    you can get line-of-sight and the distances aren't too extreme, then there
    are cheap radio alternatives.

    Miguel Cruz, Jun 30, 2003
  8. C

    shope Guest

    Can you use microwave? easiest thing in this situation if you have line of
    sight is not to use cables at all.
    A device that gives you a 2Mbps E1 or a 1.5 Mbps T1 (whichever suits your
    PBXes) would be best
    You may have issues with drive distances, and if the electric grid is not
    good, or you electrical storms then you have to protect yourself from
    interference and electrical problems.

    If you can get someone to fix it if it breaks, a better proposition may be
    fibre - no need for any amplifiers over tha distance, and no electircal or
    grounding issues.

    fibre here is pretty cheap - cost (and wieght, etc) is dependent on the
    cable construction and the amount of protection.

    Modern fibre is tougher than an unarmoured co-ax, but you may need access to
    splice tools if you get a break.
    No. used thick ethernet a lot, but that is limited to 500m per segment (and
    data only)
    shope, Jun 30, 2003
  9. C

    allan Guest

    If you need to connect the two PBX and if you want to use VoIP, first find
    out if the PBX can connect to a cisco router (VWIC-MFT card) with voice
    T1/E1, then if you have a point to point connection between location just
    link the two cisco's and that's all. Or you can just get two adtrans and do
    the same just going PBX to PBX, if there is no point to point , as the last
    resort install wireless links, I've seen very nice results using motorola
    canopy or cisco 1400s, the voice quality is very good over those links and
    you can certainly push a lot of calls over 50+Meg link (with the cisco).

    allan, Jul 20, 2004
  10. C

    Nortec in MN Guest

    Many data centered people don't know any better but there is a better
    solution: Simply install a VoIP gateway on each switch. All the major
    manufactures have them and they typically will provide a better integration,
    lower cost, and better performance than the solution stated below... and
    will be MUCH easier to troublshoot if you have issues.
    Nortec in MN, Jul 22, 2004
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