Another request will be : positive grounding instead of negative. Why? The most profi wireless equipment uses -48V with positive grounding. Our technicians did damaged some RBs placing it on the same tower like profi links and grounding it together ;-( We need to use separate independant batery circuits to avoid this issue.

Please think about it.

you can use RB800 that can use either of grounding - positive or negative. Of course, if that is your main requirement.

Thank you for your information Janisk. The RB800 is pretty big biest. It will not fit in most of our enclusures. We are now impressed about performance/prize value of 433GL, and already this board is very long when using 2 or 3 Hn cards.

just use a dc-dc converter from -48vdc to 24vdc, which is fully isolated.
we always mix professional -48vdc equipment with mikrotik +24vdc equipment using such converters. never had any issue...

you can look in this device:
http://routerboard.com/RBPOE-CON-HP

it can convert anything 48V (802.3af/at positive or negative) to 24V suitable for routerboard. Note that device has 100Mbps interfaces, not 1Gbit.

Thank you guys.
Please look at my second request http://forum.mikrotik.com/viewtopic.php?f=3&t=62777

Yes we use DC-DC convertors from battery pack (32-56V) to stable 24V, but every piece of some hardware is some kind of possible problem. So we like to see less hardware than complicated solutions.

We dont want to use converter for each unit, we like to use our Poe concentrated panels like this

but its just passive 100Mbit version.
So we are now looking for buy or build 1Gbit version.

Please dont missunderstand me, i am not searching Bugs. We are just on the way to use RBs like profesional sollution using profesional methods, like -48V batery supply, poe pannels, racks, antena towers etc.... We discover that the right way leads to solid network we like.