Ethernet Cable Shows Continuity But Camera Will Not Go On?

Hi Everyone,

The Ethernet cable shows continuity but the camera does not switch ON. What could be the problem? Consider Everything else good. (PoE, Switch, NVR, Internet, Static IP etc., etc,). But if I change the cable the camera is working.

In the previous case why the camera was not working when ethernet cable is showing continuity & everything else good???


Without knowing more, it sounds like a cable problem. Did you try re-terminating both ends? Is your cable length under the limit for both the CATx and type of POE? Did it get run past something which could be providing interference?

As to why the tester is showing a good cable, all things being equal I'd think either your cable tester isn't testing all of the pairs, isn't working properly, or the cable functions just enough to test out continuity-wise, but not well enough to carry the POE properly to the camera.

It might be worth picking up a POE tester to see what the voltage looks like.

I went through this over the phone for a long time with an installer. He "certified" the cables with a tester, etc.

The ends were terminated in order and not in "pairs".

I've had installers provide certification documents for new cable installs, which they supposedly tested and had bad runs which required replacement of cable. Maybe someone tested a cable twice, or BS'd, who knows. When they certified the cable, did they certify it for data, for POE, or both?

Again, I'd suggest re-terminating the cable ends and/or putting a POE tester on it which can provide more insight into what's on the wire. Your camera obviously isn't getting the right power via that cable. Logic to me would say if switching out the cable with an exact same cable (length, type, manufacturer, etc.) works, then it's most likely a bad cable.

Let's not get hung up on the vernacular, TIA/EIA-568B (or C now, supposedly), is the standard I'm aware of and use for cable installs. That standard defines the pin to pair assignments. Add to that POE uses positive and negative current on separate pairs of cable, so I use the term "pair."

Strictly speaking, though not good practice, as long as the cable is pinned out in a method which is compatible with the switch, POE injector, and camera; that's all that matters. A POE tester should tell you that, and if there's anything going on with the cable (e.g. damage) which prevents it from carrying the POE.

When they certified the cable, did they certify it for data, for POE, or both?

Is there a way that a cable would pass data certification and yet fail POE certification?

Are you using same cable manufacturer and same cable type when making a cable change? What standard was used during certification?

You should do a full cable test and demand a report. Even than, as stated above, someone might have mqde fake reports so if you want to be sure, test it yourself.

A simple thing as a split pair will not be detected by a 'dumb' cable/wire mapper tester but will certainly stop your link from working.