This routerboard have gigabit ports. Do it support Passive PoE?
Sorry for my English 
RB750G have five gigabit ports. Ether1 support passive POE with 100mbit speed and Mikrotik gbit POE with 1000mbit speed
What is Mikrotik gbit POE?
Thanks.
This is Mikrotik gbit POE
AFAIK passive PoE is same for 10/100/1000Mbps.
Gigabit passive PoE is marketing trick, pay more for the same thing
Regards, Grzegorz.
Can you make gbit connection with for example RB600, RB800 or RB250G with this POE :))
http://www.routerboard.com/index.php?showProduct=86
Most pasive POE not support gbit mode.
if that would be so, why don’t regular passive PoE work with gigabit ports 
?
It’s hard to say but I was wrong
Gigabit PoE need dedicated PoE injector/splitter set, like mentioned by aaa.
@Normis
Below is quotation from RB750G brochure:
Power over Ethernet: 9-28V DC on Ethernet port 1 (Only on
pins 4,5,7,8. Passive PoE. Non 802.3af). Jack: 9-28V DC
Pins 4,5,7,8 are used in 10/100Mbps passive PoE, could you explain this, please
Regards, Grzegorz.
In gbit POE pins 4,5,7,8 shared between power source and balanced signal. Same like in SatTV LNB power share coax cable with unbalanced RF signal.
common mistake 
will fix
I tested mikrotik gigabit poe adapter and I found it would only make 100Mbps connection between two gigabit devices. How would it work if it uses only 1236 poles for data and 4578 for power? I know gigabit link uses all 8 poles for data.
Now I know gigabit poe really works in gigabit mode. It has a curious toroidal low-pass filter inside that will let poe over datalines to work without having to put poe itself by “center tap” of ethernet switch transformers (as poe switches do).
I think this king of gigabit poe will only need a very good couple of gigabit ethernet card on both sides, in order to prevent data loss through this filter.
Very good work, however.