Passive POE on AR150 - No ethernet connection?


#1

Hi,

My plan was to use a TP-Link CPE210 to provide both network access and power to the AR150.
TP-Link is using passive 24V PoE @ 10/100 Mode B with DC on spares:

"Our passive PoE access points use the pinout of 802.3af mode B - with DC plus on pins 4 and 5 and DC minus on 7 and 8 (see chart below). Data is then on 1-2 and 3-6. "

Currently I don’t have anything soldered on the pins of the AR150 where the PoE module should be soldered on.

If I put in the network cable coming from the CPE210 into the WAN port I am able to measure the expected 24V between the middle pins above the network connectors. As I don’t power it yet by PoE I plugged in the USB cable to power the router. However when it boots up it won’t have a link on the WAN. If remove the PoE injector at the cable and put it straight at the switch the link is all fine without any reboot.

What is going wrong there? Due mode B and 100mbit on the PoE injector I just have power on unused pins so the other ones should work fine? As we have 6 pinouts at the POE input side I guess that will be Rx +, Rx - and Tx +, Tx - on the sides and DC +, DC - at the middle pins.

Is it because I am still powering it by USB? But I did not connect anything to the PoE pins yet!

I don’t want to solder my DC/DC converter on the AR150 before knowing that at least it is able to handle passive PoE.

My simple plan was to use a 24 V -> 5V DC/DC converter, put the 24V / GND pins of it at DC+ / DC- pinout and the 5V output pin at the 5V PoE pinout.


#2

You need to use 48V, not 24V for AR150.

According to what you do I have no idea of how it works.


#3

Well, after having a nap I thought about what could go wrong and it seems like I was right.
I don’t use the ready to go 802.3af PoE module because I have an existing ethernet cable for a TP-Link router which is powered by 24V passive PoE which is not 802.3af. As the pinouts for PoE are quite easy to use on the AR150 I wanted to attach my own PoE solution for that 24V passive link. However that failed as described before because I did not get a link if I attach the cable having 24v passive PoE.

Now I know why: The connection failed because even though the TP-Link passive PoE injector is 10/100mbit only, the switch I use fails to negotiate a connection if I don’t manually enforce 100 mbit full duplex. Works fine on the TP-Link CPE210 though without it. After enforcing the link speed on the switch everything works fine. Will keep you updated and put a report here how to power it through passive PoE as this was requested a couple of times before :slight_smile:

Long story short - If you try to do your own passive PoE solution on the AR150 and have a gigabit switch, make sure to set that link to 100mbit FDX fixed otherwise it may fail.


#4

Thanks.

I think AR150 PoE is passive, not active, by design. I am not sure why this happen.