Hi,

I am looking at using RB433's in a project, fed with 24volts DC via POE injection. If being fed by passive POE, will I be able to use the DC jack to take 24volts from to power an IP camera?

I am trying to only use a single cat5 from the base of the pole to the radio/camera.


Regards,



Andy

I doubt that you can do that. The DC socket almost certainly has some regulation circuitry on it and you can't drive that in reverse.

Assuming that the 24VDC source has sufficient current to drive both the RB433 and the camera, your best bet is probably to make up a custom CAT5 splitter to extract the power before it reaches the RB and inject the data output from the RB.

If the camera is entirely passive you should be OK, but if it contains motors for focus, tilt and zoom you may get problems with back EMFs causing interference to the RB. It really depends on how good the regulation circuity is on the camera and RB. It's certainly worth a try on a test bench and if you get problems you may need to look into getting an active power splitter.

The power will be on the Blue and Brown pairs on the CAT5 cable. The easiest way to do it is probably to use two CAT5 Y splitters as follows:-


Regards

Chris Macneill

Thanks Chris,

I have done quite a bit with passive POE pass through and break outs, but was hopeful the mikrotik's had no filtering between the passive POE and the DC jack, I have seen some devices that dont but dont have a 433 here to check for myself.

I will order a few 433's and figure out the tidiest option.

Just a query, do you run a wisp ?

Andy,

In the case of RouterBoards the issue is that their DC input can be a wide range, consequently there must be some kind of regulation between the DC port and the regulated 24VDC provided via the PoE interface.

I used to run a small WISP in South West Scotland, but unfortunately competition from copper/fibre delivered ADSL Broadband caused it to be closed down in Februrary 2008. I emigrated to NZ in August and have a job offer based in Christchurch. Currently I'm waiting for my Work Permit to come through, hopefully it won't be too much longer. I'm alternately languishing in Motels and learning to ski depending on the weather, hopefully the Work Permit is going to come through before the end of the skiing season, otherwise I'm going to rapidly get very bored.


Regards

Chris Macneill

Certainly would.

They have so many requests on their plate right now though!