Subscriber Discussion

Use 1 Cat5e For PIR + Axis P32 ?

BE
Brian Elias
Oct 12, 2016

I need to install an Axis P3225-LVE at a location where it's nearly impossible to run a new cable.  There is already a CAT5E that was run to a PIR motion sensor which uses 1 pair.

It looks like it is possible to connect the camera using the remaining pairs (see this post), but I'm not sure which pairs are required.  I'll be using a PoE switch (HP 1910 or Ubiquiti ES).

Any help would be greatly appreciated.  Thanks!

U
Undisclosed #1
Oct 12, 2016
IPVMU Certified

Yes, 100Mb ethernet require 4 wires and 2 pairs, so it may be do-able because you have 3 pairs and 6 wires free.

I say may only because its possible that the PIR pair could generate crosstalk, preventing the optimal operation of the devices or preventing it from working at all. Depends on the length and what that signal is that is already on it.

To tell you exactly how to wire it depends on which pair is in use. if the PIR is using a pair like 4+5, which is not needed by mode A 802.3af devices, then you just can use 1236 in a straightforward manner.

if you tell me which pair, by number and color, is in use, i can tell you what to do. also are the endpoints on both sides within inches of each other?

BE
Brian Elias
Oct 12, 2016

Hello and thanks for the reply.

I have full access to both ends of the cable, so I can swap the PIR to whatever pair would be best. I believe it's a simple dry-contact closure, but I'll need to check to be sure. If so, then I'll just plan to connect it to 4+5 or 7+8.

The endpoints are close to each other, but I can't imagine any issues in extending the pair for the PIR (unless you're thinking about introducing more RFI).

Thanks again.

Avatar
Brian Rhodes
Oct 12, 2016
IPVMU Certified

What is the PIR connected to? Is it tied to the video system or a separate intrusion system?

BE
Brian Elias
Oct 12, 2016

It's a separate residential intrusion system. They ran CAT5 to all security endpoints.

U
Undisclosed #1
Oct 12, 2016
IPVMU Certified

sounds like a low-frequency signal, so it should be ok.

leave a note for the next guy...

UM
Undisclosed Manufacturer #2
Oct 12, 2016

Disclaimer: I work for Axis. If the PIR is 12V DC, you can connect it to a few different models of our cameras that have I/O's. For example, the P1425-LE or M3026-VE have I/o's that can power small 12V devices. You can see the info on our website for our PIR devices, but you should be able to use the existing one. The P32's don't have I/O's however, so if you've already bought that model you'll have to go with one of the methods discussed here.

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