I have this splinter of 6 different PoE switches connected the all compliant 802.3af. Unfortunately, the splitter has only works on a single switch, and indeed the only on the single Fast Ethernet (100Mbps / s) supported. At all Gigabit switches the voltage cancels every second to 2V and then slowly builds up again on the 5V.
For 100 Mbit / s, the voltage for PoE is placed on the two free wires and only that can frag ancheinend ...