mgthump wrote:Will not power a cambium 320 with pins 4 and 8 reversed to match the devices pin out.
the unit powered up, but when CPEs registered the graph hit 36 watts and I heard a pop in the switch, and I've killed my switch testing :/
They're just to hungry for the power budget once the air interface gets active :(
Cambium 320 (wimax) APs are powered on pings 4,7 - and pins 5,8 + same pin out as the 430 APs. the 320s and the Alvarion wimax have the same power specs and i've heard they are the same gear in the box, but I've never cracked on open to look.
Pin 4 is from Pair 3 which is Positive polarity Pair
Pin 8 is from Pair 3 which is a Negative polarity Pair
I would never mix Pairs which is a cross short of pairs which is bad.
I have heard of companies swapping polarity on a "Pair" but never mixing polarity on the same pair as that will FRY any Ethernet transformer.
For instance there are 4 pairs and 8 pins
Pin 1 - Pair 1 - DATA - Orange/White
Pin 2 - Pair 1 - DATA - Orange
Pin 3 - Pair 2 - DATA - Green/White
Pin 4 - Pair 3 -
POS - Blue
Pin 5 - Pair 3 -
POS - Blue/White
Pin 6 - Pair 2 - DATA - Green
Pin 7 - Pair 4 - NEG - Brown/White
Pin 8 - Pair 4 - NEG - Brown
By Swapping Pins 4 and 8 you were doomed from the start as you were mixing Polarity on the Ethernet Transformer Pairs.
THE ONLY WAY THAT COULD EVEN WORK IS IF THIS DEVICE IS 10/100 ONLY AND THEY ARE NOT PUSHING POWER FROM PAIR 3 AND 4 THROUGH A CENTER TAP ETHERNET TRANSFORMER BUT WHY WOULD THEY MIX POLARITY ON PAIRS AS THE PAIRS ARE TWISTED AND THIS WOULD CREATE SMALL ELECTROMAGNETIC FIELDS. POLARITY SHOULD ALWAYS BE KEPT TO A PAIR NOT MIXED ON A PAIR. WHAT HAPPENS WHEN YOU WRAP WIRE AROUND SOMETHING AND APPLY DC POWER?!And if that is a 10/100 device doing something like that you must realize that our switch is a 1G device which means we have to be using a 4 channel Ethernet Transformer and thus all 4 pair are going through a center tap transformer.