Hi, folks: I just took delivery of new PoE cables (PN 2200-11077-002) for our Polycom phones here in the office.
I have the following to report, for the erudition of existing Polycom users and those considering purchasing Polycom sets from the set of models noted in the subject: 1. The cables do indeed work (hooray). 2. The cable has a module on it about a third of the way from a female end. The module is about the size and shape of a large cigarette lighter or a small bar cellphone; it has a green LED indicator on it, which illuminates when the connected device is drawing power. The module also has a receptacle for the DC end of a Polycom power adapter. Presumably these cables can replace the default external AC injection cable completely. The module, for those who are interested, provides ground-loop detection and protection. Early revisions of the 802.3af standard did not provide for ground-loop protection in the midspan, and so phones would overload (and fry) PoE midspans (this is strong evidence that there were no telecom engineers in the 802.3af working group, since ground-loop protection has been a necessary part of PSTN systems since the dawn of time). I suspect newer midspan equipment is not burdened with this problem, which would explain why some people can use garden-variety cables with these phones on PoE. 3. I thought I might save some clutter by putting these cables between the midspan and the patch panel, but then I discovered that the male end of the cable is keyed, just as in the default AC cables provided with the phones, meaning that they'll only work if plugged directly into the phone itself. The reduction in clutter with this set-up is, unfortunately, not what I had hoped, though anything is better than nothing. I imagine it would work if I sanded away the plastic post on the connector, but that says nothing about how it might behave if a non-compliant device were plugged into it. Better safe than sorry. Cheers, -Stephen- _______________________________________________ --Bandwidth and Colocation provided by Easynews.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
