I think the term PoE cable is what may be confusing here.
Let's limit this discussion to Cat5e and Cat6 cable types.
In this case, there is no 'PoE cable'. Whether or not power is provided along with data is dependent upon the equipment the cable is connected to, not the cable itself.
As an example of this, let's say you run a Cat6 patch cable from a non-PoE switch to a camera. That cable is carrying data only at this point. If you take that same exact cable and connect it to a PoE switch and the camera (assuming the camera is PoE capable also), the cable will now carry data and power by nature of being connected to a PoE switch.
So let's say you want to use an injector. In this case, commonly you will have a non-PoE switch connected to a PoE injector (data only from switch to injector). You then plug a cable into the 'Out' side of the PoE injector and the other side into a camera. This cable is now carrying power and data from the injector to the camera.
The purpose of an injector is to provide PoE power to a device (i.e. camera) that would otherwise connect to a non-PoE switch.
Does this help clarify?
IPVMU Certified | 05/19/15 05:47pm
Ken, all category cables are POE capable. All ethernet switches are not POE capable however.
If you need to connect a non-POE switch to a camera that can only be powered by POE, then you would use an injector after the switch and before the camera.
An injector will typically have two inputs, a power source and ethernet data source (category cable) which it will combine and output on one category cable. This cable cable can now power the camera and connect it to the network. Here's one example.
edit: just saw Matt's response and agree
Cables are cables.
PoE can work properly on cables that were installed before PoE itself was even a glimmer in an engineers eye - because standardized cable specs and pinouts ensure things will work.
This is why it's important that you follow proper installation guidelines for cable plants, you never know what next-gen technology is going to be based on the assumption that your installation was done to spec.