Powering Cisco phones from non-Cisco switches/injectors

Discussion in 'Cisco' started by KR, Jan 8, 2006.

  1. KR

    KR Guest

    I've noticed that the majority of 802.3af PoE-compliant equipment out
    there will NOT work with Cisco 7905, 7912, 7940 and 7960 IP phones.
    D-Link PoE switches and ZyXEL injectors, for instance, do not work.

    However, some equipment do work (provided one makes a "PoE crossover
    cable" for the 7940/60), like the 3Com PW130 and Dell switches w/PoE.

    So I wonder:

    1. Is there a list somewhere of non-Cisco equipment that do work with
    these phones? Some advertise support for the CDP protocol, but even
    without CDP support, some PoE injectors still work ("dumb" units that
    basically provide power no matter what).

    2. Is there something I can do to make 802.3af switches/injectors
    provide power to non-802.3af compliant equipment? Say, a hardware mod to
    "fool" the discovery protocol? According to the specs, it would seem
    that a 25kohm resistor across 1-3 (or 2-3 or 3-6) ought to do it.
     
    KR, Jan 8, 2006
    #1
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  2. KR

    papi Guest

    Panduit has mid-span patch panels (pretty nice for old legacy stuff, like
    I had to deal with), compatible with old inline powered Cisco devices (as
    well as 802.3af, of course):

    http://tinyurl.com/82qye

    HTH,
    Papi


    On Sun, 08 Jan 2006 21:55:32 +0100, KR wrote:

    > I've noticed that the majority of 802.3af PoE-compliant equipment out
    > there will NOT work with Cisco 7905, 7912, 7940 and 7960 IP phones.
    > D-Link PoE switches and ZyXEL injectors, for instance, do not work.
    >
    > However, some equipment do work (provided one makes a "PoE crossover
    > cable" for the 7940/60), like the 3Com PW130 and Dell switches w/PoE.
    >
    > So I wonder:
    >
    > 1. Is there a list somewhere of non-Cisco equipment that do work with
    > these phones? Some advertise support for the CDP protocol, but even
    > without CDP support, some PoE injectors still work ("dumb" units that
    > basically provide power no matter what).
    >
    > 2. Is there something I can do to make 802.3af switches/injectors
    > provide power to non-802.3af compliant equipment? Say, a hardware mod to
    > "fool" the discovery protocol? According to the specs, it would seem
    > that a 25kohm resistor across 1-3 (or 2-3 or 3-6) ought to do it.
     
    papi, Jan 9, 2006
    #2
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