POE is quite the crackwhore of terms nowadays, alot of people use her in alot of different ways and nobody wants to pay much. I wish there was just a design standard that just auto sensed and applied, 24v 48v pick a pair. Just to eliminate the additional stocking of appropriate power supplies and surge suppression, they would be worth a little more, and if it were to become common the cost would drop
On Mon, Jan 4, 2016 at 5:30 PM, George Skorup <[email protected]> wrote: > I believe Phihong wired it that way so that you can use it as a 3at > compliant injector where only two pairs may be present (so 10/100 only). IP > phones come to mind. We run into a lot of older-ish structured wiring where > they ran only one cat5 and stole one pair for phone and two pairs for > ethernet. Not the way I'd do it, but whatever. Most of the phones we're > using now have a built-in GigE switch. > > I remember seeing in the 450i guide that it will take either polarity on > all pairs. If you're not using the aux port, then two pairs for power (30W) > will be fine. If you are, or I suppose if it's a long run, then all four > pairs for power would be warranted. I really like this PoE design. Would be > nice if the regular 450 APs would take 48-56VDC. I know they talked about > that at one point, but it looks like we're limited to 30VDC. Well, at least > that's what the label says. > > The whole pin swapping thing with the 450i and CMM4 is because 56VDC mode > on the CMM4 is wired for the split pair 320/430 config. With the AP being > pair polarity agnostic, you don't need to do the swapping when using a > SyncInjector. Basically it will take the standard Canopy POE pinout, just > needs to be >=48VDC. Probably more like >40VDC. > > On 1/4/2016 12:50 PM, Ken Hohhof wrote: > > Good point about the power being on 1/2 and 3/6. I guess that makes it > 802.3at Alternative A wiring. According to the schematic, 4/5 and 7/8 are > wired straight through with no transformer. So gigabit compatible with > only 2 transformers. Probably for non gigabit compatible, Alternative B is > cheaper because you don’t need any transformers at all. And the 60-75 watt > POEs use all 8 wires for data and power, so 4 transformers. > > So confusing! > > I can’t find any wiring diagrams for the Cambium N000065L001B, but at 60 > watts, I guess it must use all 8 wires for power. Hence the price? > > Something else I notice is the Cambium POE is rated for 0 to 40C, while > the Phihong unit is rated –20 to +65C. Cambium tells you to use a PIDU for > non controlled environment. Or Netonix or GIGE-POE-APC or Syncinjector. > > Still, AC powered POEs are handy for configuring radios on the bench, or > like that case where I needed a POE at a customer’s office to power a SIP > paging amplifier. > > > *From:* George Skorup <[email protected]> > *Sent:* Monday, January 04, 2016 2:35 AM > *To:* [email protected] > *Subject:* Re: [AFMUG] 802.3at POEs > > It's cheaper at Allied: > http://www.alliedelec.com/phihong-poe36u-1at-r/70124112/ > > Yeah, if you're not going to use the Aux port on the 450i, there's no > reason to buy a 60W injector. Just keep in mind that this Phihong injector > is power over the 10/100 data lines. And is - on 1&2, + on 3&6. It'll work > perfectly fine with the 450i APs and 5GHz SMs. And obviously the Exalt > ExtendAir G2. The 450i is awesome with the any pair power setup. > > The one thing I will say about this thing is that it runs a bit hot and if > your hearing is decent, you can definitely hear the switcher whining away. > > On 1/3/2016 7:29 PM, Ken Hohhof wrote: > > I'm getting more and more equipment with 802.3at POEs, and I feel like I'm > getting raped on the price if I get the POE from the equipment vendor. > High price and minimal features. > > My Exalt G2 radios came with these really nice POEs that have diagnostic > LEDs and tabs for wall mounting as well as rubber feet for desktop use. > The only downside is they are kind of big, but that's not necessarily bad, > that may help prevent overheating. It has LED indications for valid > 802.3af and 802.3at signatures, as well as a flashing overload indication. > > I looked up the part number, expecting them to be expensive, but Digi-Key > has a bunch of them in stock and the price is quite reasonable ($38 in > single quantity). > > <http://www.digikey.com/product-detail/en/POE36U-1AT/993-1088-ND/2384576> > http://www.digikey.com/product-detail/en/POE36U-1AT/993-1088-ND/2384576 > > From the picture, this is also the POE that I should have gotten from > CyberData to go with the SIP paging amplifier I bought, but instead they > sent a cheaper L-Com POE that has just one dumb LED to show it is getting > AC power. So I paid something like $64 for a $31 POE. > > The $100 Cambium POE for 450i is probably more than 36 watts in case you > want to use the AUX port on the AP, but it lacks the nice mounting tabs and > diagnostic LEDs. And 36 watts should be more than enough to power just the > AP. > > So I’m inclined to just buy a bunch of the nice Phihong units and use them > on everything. Am I missing something? > > > > -- If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team.
