Trango Apex Lynx is -48V (positive ground). I have that verbally from
Trango, but also I have them mixed on the same DC bus with -48V
wimax/LTE equipment. They could be agnostic....but if they were +48V I
would have smoked equipment 20 times over.
If you're meaning Apex Plus then I don't have any of those, but it would
be a strange choice for Trango to make them opposite.
I don't have answers on any of the others.
If you have physical access to the equipment, power it up and check for
voltage and/or resistance between the ground lug on the device and + and
- terminals of the power supply.
On our -48V Wimax stuff I can disconnect the + terminal on the PSU and
the device will stay on. That's a less definitive test...depends on how
everything is grounded.
I believe 802.3af compliant stuff is supposed to be isolated. I believe
the reason is that if they start grounding one side or the other then
people would start popping their switch ports. Also with power over the
data pairs, grounding the power is equivalent to grounding the data, and
802.3 requires a specific amount of isolation between data wires and
ground (for reasons above my pay grade). I suppose every device
accepting 802.3af power doesn't have to be 100% 802.3af compliant
though.
------ Original Message ------
From: "Bill Prince" <[email protected]>
To: "Motorola III" <[email protected]>
Sent: 4/18/2017 8:17:56 PM
Subject: [AFMUG] Radio power polarity
We have a site with a plethora of different equipment on 48 volts, but
we're not sure of the polarity (or if the equipment cares). We would
like to consolidate the gaggle of 48V POE inserters that we're
currently using there.
We know for a fact that our Trango Apex radios are all positive 48V
(-48 ground reference).
What we're not sure of is whether these radios ground which leg, or
don't care:
Cambium PMP450MCambium PTP650Cambium PTP650LRedline AN-80iUbiquiti
AF24Radwin 2000
They all use different pinouts, with a couple of them compatible with
802.3af, but I don't know if they care about polarity. Any clues?
--
bp
part15sbs{at}gmail{dot}com
