Good day Picers

Does anyone know what is the maximum cable length that 2 PICs can communicate over, or is there another way to do for instance 30 meter communication.
Is it also possible to share one power source over the long distance cable?

I want to have 1 base station that communicates with a couple of client stations with between 5 meters and 30 meter distance between the stations?

Thank you very much
koossa