I just purchased a TP Link PoE switch (TP-LINK TL-SG1008PE 8-Port Gigabit PoE Switch, 8 POE ports, IEEE 802.3at/af, Max Output 124W). I have no problem with it powering one of my Ubiquiti AC Access point which is 802.3at. Mikrotik claims this is also 15-60V DC, 802.3af/at supported. But when I plug the cable straight into the TP Link switch (tried multiple ports, it never powers up. Only seems to work with the PoE injector.
Im trying to reduce the clutter and get rid of the PoE injector.
The brochure mentions this particular line “15-60V DC, 802.3af/at supported (Mode B. requires crossover cable)
Packaged with 24V DC 0.8A power adapter and passive PoE injector”
Does that mean I need a special ModeB crossover cable? Im probably going to need a special female side on one side and male on other (like the way the PoE injector they include) since mine already has a male RJ45 plug for the Cat5 coming from the SXT AC.
Damn it, seems like Mikrotik is using Mode B. This TP Link and most PoE 802.3at switches seem to be Mode A. Mode A puts power on pin 1/2 and 3/6. Mode B does power on ping 4/5 and 7/8.
Now time to search for a “conversion” cable if they even make one.
I don’t understand how this Mode B requires crossover cable. There no way a cross over cable will convert a modeA to modeB.
Im not following the specs on this now. It says its 802.3at compatible which is what my switch is. Is there any data sheet that shows specifically what pins requires power?
Seems like the Mikrotik is not truly 802.3af/at compliant. If it was it should be able to handle ModeA. Here is an example, I have as I mentioned a Ubiquiti AC AP, also came with a passive injector, that is the picture in black, notice it is shooting voltage in ModeB form. But it has no issues hooked up to my TP Link PoE switch which is outputting voltage as Mode A. So it is compliant.
Mikrotik injector pictured below in white, shows its injecting on Mode B pins, yet the SXT AC refuses to power up on Mode A based voltage which leads me to believe it doesn’t actually comply with the 802.3af/at spec which states that “While PDs must support BOTH Mode A and Mode B to be compliant with the 802.3af standard”. The brochure clearly states its 802.3af/at compliant.
This is a bit frustration that I have these now either need to replace the Mikrotik’s or now get a PoE switch that does both ModeA and ModeB.
There was a pretty similar discussion about the mAP2n and in the end, they changed the documentation not to mention 802.3 PoE. Plenty of websites only ever used the first draft and still show specs saying that the device is 802.3af. Perhaps if you open a ticket, Mikrotik will update the specs.
Those specs are still on the data sheet itself right off Mikrotik’s website. Man this is frustrating, now I have a switch that is basically useless for Mikrotik devices. They have it written in there that its 802.3af/at supported. That’s why we bought this $300 plus switch.