Can somebody show me how a Gigabit PoE injector is wired? Is the wiring of an RBGPOE different from an RBPOE?
I am a bit confused because I thought I understood that Gigabit uses all four pairs for data and yet the wording in the brochure for the RBGPOE injector http://routerboard.com/pricelist/downlo ... ile_id=309
suggests that the wiring is exactly the same as a 10/100 PoE injector (i.e. pairs 4,5 and 7,8 are unused, and power/ground are supplied over them).
If pair 4,5 is used for "+", does this mean that the PoE injector ties wire 4 and wire 5 together? (in which case they would be shorted out, and differential-mode data could not be sent over this pair) Or does it insert "+" power via a diode onto each of them (and a complementary arrangement on 7,8)?
FWIW my motivation in asking this is to know how I should manually field-modify devices (such as RB250GS, RB750G) to provide field-expedient PoE.