Netonix Forums

sirhc wrote:*********************************
24V POE Option @ .75A - constant draw can surge/spike to 1A:
802.3af/at MODE B pinout
Pair 3 / PINs 4, 5 are POSITIVE
Pair 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE

Enabling 24V POE Option @ .75A on WS-12-250-AC gear I have noticed that ports #1-6 have
Pair 3 / PINs 4, 5 are POSITIVE
Pairs 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE,

but port #7-12 have
Pair 3 / PINs 4, 5 are POSITIVE
Pair 4 / PINs 7, 8 are NEGATIVE

is there a specific reason why ports #1-6 have pair 2 NEGATIVE and ports #7-12 do not have pair 2 NEGATIVE?

-Florian

because the upper ports on this model only have positive power on a single pair, so no ground required on the "upper" pair....lower ports are VH (power on all 4 pairs)..upper ports are V power, power only on two pairs

But ports #5-6 are also 24V/48V @.75A only, but these ports supply: pairs 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE
ports #7-12 supply: pair 4 / PINs 7, 8 are NEGATIVE

sigh..sorry, i missed that...this is because this board is also used in the ws-12-400-ac product, so by default, ports 5 & 6 do have both ground pairs attached to ground.

May it cause issues connecting ports #1-6 with passive 24V PoE equipment using shielded cables if pair 2, pins 3,6 are also negative?

should be fine, it has been this way for many years, and many thousands of switches sold