Netonix Forums

Any suggestions for running the Netonix WS-12-250DC in a -48VDC environment? On it's own, it works great, powers up, etc. With UBNT Titanium 48V radios, it also is working great. When we plug in 24V RocketAC Lite radios, the ground plane of the RPSMA connector, is bonded to the tower (via the antenna) which then sends -48V through the radio and out pins 7,8 down to the switch to the return (which is the positive 48V connector on the switch). This fries the ethernet port that the netonix is plugged into, not bad enough that it dies entirely, but it's no longer capable of delivering power or data on pins 7,8. So you're limited to 10/100 ethernet, no power.

Most of our sites are +48V, but when we have to share sites with other telco providers, we end up in situations like this. I'd love to hear any recommendations you might have. For the record, our typical fix is to feed the +48V device with an isolated DC/DC power supply, but in this case when we connect the netonix to it, the power supply shuts off, probably a polarity protection circuit, but we can't see any voltage passing between the chasis of the power supply and any of the isolated power leads.....stumped.

Hi..i am new to this forum. I recently started working as a network engineer. I want to learn about the concepts of the networking with the Netonix modules. Can you please tell me about WS-12-250DC an why it needs -48V? I saw this at many other places also that hubs are working at -48V, can you tell me its reason?

OraleeOrav wrote:Hi..i am new to this forum. I recently started working as a network engineer. I want to learn about the concepts of the networking with the Netonix modules. Can you please tell me about WS-12-250DC an why it needs -48V? I saw this at many other places also that hubs are working at -48V, can you tell me its reason?

It does NOT want -48V, in fact we warn people not to use NEGATIVE 48V

The WS-12-250-DC will accept 9-60V DC and still power 24V and 48V devices including airFIBER 24 / 5 radios

It monitors your DC input and current

If you want to learn about our switches there is a large forum here to read and search for questions.

You can also watch the video https://www.youtube.com/watch?v=8JvBEAD4MFM

Chris, do you have any creative solutions we can use to colocate a netonix 48VDC switch in a negative 48V environment? Isolated DCDC transformer maybe? We don't really have a choice in this and a few of our other POPs.

OraleeOrav wrote:Hi..i am new to this forum. I recently started working as a network engineer. I want to learn about the concepts of the networking with the Netonix modules. Can you please tell me about WS-12-250DC an why it needs -48V? I saw this at many other places also that hubs are working at -48V, can you tell me its reason?

-48VDC is used in the telecom world to limit battery terminal corrosion, like the nasty green crystal buildup you commonly see on automotive 12V batteries.

http://archive.digivation.net/2006/08/1 ... -volts-dc/

There was someone that posted up a solution on here in one of the threads.

I am pretty sure they got it from Streakwave or Ebay, or something like that?

I will ping Dave and see if he remembers.

Hi,

I am powering an AirFiber 5U unit in a -48V cellco tower we are colocating at. We ended up using an isolated DC-DC converter, after confirming that the tower's ground bus was actually tied to ground and to utility power ground, so no loops could take place. Tycon systems makes a wide range of DC-DC converters. All you need is to feed it the -48V DC and it will supply +48V on the other side.

This one injects directly into an Ethernet port:

http://tyconsystems.com/index.php/dc-pa ... -4856g-vhp

but you can look at their direct DC conversion versions.

Cheers,

Mike

Thanks Mike,

Unfortunately, we need to power more than a single radio, which is why we're hoping to get the netonix DC powered off -48Vdc. We tried an isolated DCDC converter from Meanwell, but despite the Netonix chasis being isolated from ground, we're still getting a return voltage on the negative side. I hate these puzzles...

I want to learn about the concepts of the networking with the Netonix modules. Can you please tell me about WS-12-250DC an why it needs -48V?





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