PoE (active, 803.3af/at, two pairs) has power limits. the max power a PSE can provide:
af=15.40 W
at=30 W
and current:
af=350 mA per pair
at=600 mA per pair
This means for the higher spec at that 30 W / 57 V= 526 mA max
The Mikrotik reduces this (on PoE out ports) to 440mA.
These same PoE out ports can be used as PoE in ports with Passive PoE (Mode B), but there is no reason to presume that the accepted current in will in will be more than 440 Ma.
On the other hand, the higher bt specs have 90 W and raise the allowed Amperes on a pair to 960 mA, so pushing 1A might be fine (in the sense that the cable will be able to carry that current without overheating).
So, to your questions:
1. Mode B means that the + is on the pair 4,5 and the - is on pair 7,8, this is what the Mikrotik will accept, what is put on the line depends on your power supply/injector.
2. You can push as many A as you want, but if - as I believe - the 440 mA limitation is bi-directional they won't get through, BUT you can put a PoE splitter (passive), and extract the power from the ethernet cable and feed it to the RB5009 jack or two pin DC input (NOT on one among ether2-8).
The MIkrotik RBGPOE is reported as being capable of being used both as an injector and as a splitter.
https://mikrotik.com/product/RBGPOE
viewtopic.php?t=179651
(you will need a gender-changer for the jack)
The RB5009 will get all the current available, your 3 cameras+ 1 other device, will draw up to 15 W each, and everyone will be happy.
af=15.40 W
at=30 W
and current:
af=350 mA per pair
at=600 mA per pair
This means for the higher spec at that 30 W / 57 V= 526 mA max
The Mikrotik reduces this (on PoE out ports) to 440mA.
These same PoE out ports can be used as PoE in ports with Passive PoE (Mode B), but there is no reason to presume that the accepted current in will in will be more than 440 Ma.
On the other hand, the higher bt specs have 90 W and raise the allowed Amperes on a pair to 960 mA, so pushing 1A might be fine (in the sense that the cable will be able to carry that current without overheating).
So, to your questions:
1. Mode B means that the + is on the pair 4,5 and the - is on pair 7,8, this is what the Mikrotik will accept, what is put on the line depends on your power supply/injector.
2. You can push as many A as you want, but if - as I believe - the 440 mA limitation is bi-directional they won't get through, BUT you can put a PoE splitter (passive), and extract the power from the ethernet cable and feed it to the RB5009 jack or two pin DC input (NOT on one among ether2-8).
The MIkrotik RBGPOE is reported as being capable of being used both as an injector and as a splitter.
https://mikrotik.com/product/RBGPOE
viewtopic.php?t=179651
(you will need a gender-changer for the jack)
The RB5009 will get all the current available, your 3 cameras+ 1 other device, will draw up to 15 W each, and everyone will be happy.
Statistics: Posted by jaclaz — Mon Feb 10, 2025 8:41 pm