Let's Control It

I'd appreciate some help with a couple of questions:-

Is there any advantage is using a separate power supply?
Could anybody please supply plug polarity and optimum voltage?

Many thanks in anticipation.

What do you want to power?

I wish to provide a separate power source to the rflink. A power connection is provided but I don’t have the optimum voltage or polarity for it.

I don't know what the power requirements are of the RF link, so I am afraid I cannot be of any help here.