DIY POE 8 port switch

[StealthRT]

Hey all i am trying to modify a Netgear GS108 8-Port gigabit switch with POE on 4 of the ports. Problem is that when i go to test to find out what pins 4/5 and 7/8 are in order to place the positive and negative terminals too, it shows continuity on every pin of echo of the 8!

So in other words, no matter what pin i test for, it always shows continuity so i never know what pin is not being used!

Here is a picture of the board:
**broken link removed**
**broken link removed**

Any help would be greatly appreciated since i do not want to fry it )

 

[StealthRT]

Hum it would seem that gigabit switches use all 4 pairs of wires :/

Oh well.

 

[KeepItSimpleStupid]

Yes, GBE does use all of the wires.

If you want to add POE, look for a MIDSPAN injector and you don't have to modify the switch. POE is still a little crazy.

Your right, there were and probably still are some 100bt injectors that use the spare pair without a signature and there are some "proprietary" formats that even boast 100 W.

They raised the voltages to 57 V DC and used both pairs to increase the current and lower the voltage drop. Furthermore the signaling is two tier. One for POE and a second to address POE+

 

[StealthRT]

If i were to connect pins 4/5 (positive) and 7/8 (negative) to the first 6 ports (ports 1-6) i understand that they would be forced to use 10/100mbps instead of 10/100/1000mbps. That being said, would the other 2 ports (7 & 8) be forced to use 10/100mbps as well or would they operate at the normal 10/100/1000mbps?

 

[KeepItSimpleStupid]

No clue.