WS-12-250-AC 24V PoE Option 0.75A - NEGATIVE on pair 2

[Flo]

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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

[Dave]

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

[Flo]

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

[Dave]

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.

[Flo]

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?

[Dave]

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