Powering a Cambium Force300 from a DC switch

[DruidGetafix]

I am seeing devices being sold to supply power specifically to the Cambium Force 300 from a DC source. The reason being given by our local Netonix distributor is that the Netonix switches such as the
WS-8-
150-
DC do not work with the Force 300. The discussion on some threads here seems to indicate otherwise.
If anybody definitively knows whether the Cambium Force 300 will work with the Netonix DC switches and what (if any) precautions need to be taken to achieve this - I would appreciate the confirmation and information.

[sirhc]

I am not familiar with this radio but all the information you need to figure this out on your own is laid out in this post:
viewtopic.php?f=6&t=1178#p8809

*********************************

Question: Can I power this device with Netonix.

Answer: Our switches are "passive" POE which means if POE is enabled on a port the power is live so if you plug in a cable that is shorted or the piece of equipment is bad or has an incompatible polarity PIN OUT you will damage the port in the switch and probably the equipment, this damage is not covered under warranty.

There are 4 Pairs and 8 PINs in an Ethernet Cable:
Pair 1: White Orange.(PIN 1 ) & Orange.(PIN 2) is POSITIVE
Pair 2: White Green...(PIN 3) & Green...(PIN 6) is NEGATIVE
Pair 3: White Blue.....(PIN 4) & Blue.....(PIN 5) is POSITIVE
Pair 4: White Brown..(PIN 7) & Brown...(PIN 8) is NEGATIVE

24V POE Option @ .75A - constant draw can surge/spike to 1A:
802.3af/at MODE B pinout
Pair 3 / PINs 4, 5 are POSITIVE
Pair 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE

48V POE Option @.75A - constant draw can surge/spike to 1A:
802.3af/at MODE B pinout
You would use this option to power most 802.3af/at devices like IP Phones and Cameras
Pair 3 / PINs 4, 5 are POSITIVE
Pair 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE

24VH POE Option @1.5A - constant draw can surge/spike to 2A:
802.3af/at MODE A & MODE B pinout combined
Pair 1 & 3 / PINs 1, 2, 4, 5 are POSITIVE
Pair 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE

48VH POE Option @1.5A - constant draw can surge/spike to 2A:
802.3af/at MODE A & MODE B pinout combined
Pair 1 & 3 / PINs 1, 2, 4, 5 are POSITIVE
Pair 2 & 4 / PINs 3, 6, 7, 8 are NEGATIVE

So now that you know what the PIN OUT is (which is in our Spec Sheet on page 17 and in the product description on our web store) all you need to do is look at the spec sheet from your device and see which POE option you can use.

If they do not specify the PIN OUT polarity break out a multi-meter and cut one end off of a patch cable and strip the wires and figure it out on your own.

Also if they have a bridge rectifier circuit like MIMOSA the device will swap the polarity the way it wants it.

WARNING - If your equipment is not specifically designed to accept power on all 4 Pairs do NOT use a VH POE option.

*********************************

[DruidGetafix]

For what it's worth, this is what I can glean from the docs of the device that is being sold to power up the Cambium radio from DC.
Cambium Force 300 uses a POE that supports passive Mode B power output (+ pin 7,8 and – pin 4,5)(Reverse polarity) and data over all 4 pairs.

The POE supports power use up to 70W .

I have no idea why the distributors are saying that this radio will not work with the Netonix DC switch. Seeing as we have Netonix DC switches at nearly ALL our high sites, I would way prefer a solution that did not require installing some special power equipment just to power up one radio.

Perhaps the solution is just one of making up a special cable? Before I go and blow something, I'd appreciate an opinion on that idea, and what specifically should be connected to what.

[sirhc]

Well our switch provides polarity opposite of what they are calling out.

We has positive on pins 4,5 and negative on pins 7,8

Now if this is a 1G port that means all 8 wires are used to achieve 1G whereas a 10/100 only device uses pins 1,2,3,6 for data and you could swap 4,5 with 7,8.

Now "maybe" the radio has a bridge rectifier like MIMOSA radios which will correct the polarity but if not and you power it up with our switch - POOF

Or you could use a dongle that SW sells that swaps polarity on pins 4,5 with 7,8 but then you would only ever get a 100M link.

BE CAREFUL WHAT EVER YOU DO HERE

[DruidGetafix]

We are using the Netonix switches extensively on all types of Cambium radios - Force 190, Force 200, ePMP1000 (sync and non-sync), ePMP2000, PMP450i, PMP670, cnPilot e410, cnPilot e500 - and on none of these did we need to modify any cables - the devices simply work with the standard cabling. That in spite of the fact that many had opined online that the did need the cable swapping. So, it would appear that you are probably correct about them containing a bridge rectifier.

The only radio we have not tested so far is the Force 300. I am extremely hesitant to take chances with this radio due to all the factors already mentioned and the fact that someone has gone to all the trouble of creating a DC device to power this radio.

However, that being said, the POE that came in the box looks identical to the Force 200 one........

[sirhc]

Use a voltmeter and map out the polarity of the POE adapter

[DruidGetafix]

The POE adaptor is definitely putting out +30V on pins 7,8. The return is on pins 4,5. However, the interesting this is that the POE adaptor that is used on the Force 300 is identical to the one used on the Force 200. And we have been using the Netonix without issue on the Force 200 for the past year.

SO, the one, untestable (well, without possible smoke) possibility remains - that the circuitry on the Force 300 is different to that on the Force 200. I am leaning towards giving it a go. After all, why would Cambium suddenly drop that safeguard from their radios if they have had it included all along?

[sirhc]

Well one way to test it and only risk the radio would be to use UBNT POE bricks which match our polarity pin out.

If the UBNT POE brick powers it without smoke then our switch will as well.

Why risk 2 devices

[DruidGetafix]

Okay - so, wrapping this up.....

I tried using a Ubiquity POE with 24V output and +ve on pins 4,5 and plugged this into the Cambium Force 300.
The good news is that no smoke came out.
The bad news is that it does not power up the Force 300.
The really good news is that when I plugged it back into the Cambium POE, the radio came back up perfectly happy.
So, in a nutshell, whilst it appears it is safe to use the wrong polarity on the Force 300, it is pointless, as it does not power the radio up. This is not true of any of the other Cambium products in the same line eg. Force 180, Force 190 and Force 200 all work with the reversed polarity of the Netonix.

Bottom line - a Netonix switch cannot be used to power up the Cambium Force 300. It does no damage, but it does not work.

[jpaine619]

You are taking into account that Ubiquiti POEs are active POE, correct? Assuming that the polarity will not damage a particular radio is in error. All you've confirmed through your experiments is that Ubiquiti POEs will not damage it. It is highly likely that the Ubiquiti POE is not getting the correct feedback it is expecting from the remote device and is never bothering to send the voltage down the line. No damage occurs because no voltage is present. You can confirm this by testing the ends with a multimeter. You'll never see any voltage (beyond the tiny check current) because your multimeter cannot give the POE the correct feedback.

A passive POE is simply going to dump the voltage down the cable without checking for feedback. I suspect that one of these devices would seriously damage your radios if your wiring is wrong.