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New Member

Cable length limitation from PoE switch and Camera

Our ethernet based network design requires PoE switch connected to five IP CCTV camera through ethh. It is not clear maximum length of cable allowed between switch and camera. Can anyone explain?

4 REPLIES

Cable length limitation from PoE switch and Camera

I think there are 2 answer to this question.

The first is

150 meter.

The second answer is,

There is no limit. You just need to make sure that the camera still receives enough voltage to work, iow you measure the remaining voltage, and if you go above the 150 meters of cable the link must operate in full duplex, 10 100 or GIgabit is up to you as long as the duplex is full.

Cheers,

Michel

New Member

Re: Cable length limitation from PoE switch and Camera

Thanks Michel for your answer. Also the question is whether voltage drop calculation is required to make sure proper voltage at Camera ? Any formula for that calculation ?

Also normally full duplex communication is available in market between switch and camera?

Re: Cable length limitation from PoE switch and Camera

Better measure then calculate, but calculation is simple if you know the current mA used bij the camera and the resistance Ω of the cable.

The current times  the resistance gives the voltage drop over the cable. This you subtract from the voltage given by the switch.

I think the camera will do what the switch proposes for speed and duplex

Cheers,

Michel

Blue

Re: Cable length limitation from PoE switch and Camera

If the cameras use 802.3af POE or 802.3at POEPlus Type 1, cat.3 and better cabling is required, with the attendant length limitations in ethernet applications.

If it's 802.3at POEPlus Type 2, cat.5 and better cabling is required, with the attendant length limitations.

Non-standard POE (such as "passive" POE)? What is that?

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