Ok.... I am not a phone person at all. I just got voluntered to do this at my company. We are looking to aquire a building across the street from our current locaton. I was having a company run 12 fiber lines underground to connect them. Now to get the phones to work I need copper and not fiber lines is what my normal phone support company is saying. He is telling me I need a multiplexer. Now is there another way of doing it.

I have an NEC digital phone system, that is not running on VoIP. I have found boxes that convert fiber to cat5 but I only get 4 pairs for the use on 1 fiber line. That is pretty minimal. Would just hooking it up to a switch not work? I am very uneducated in this and google is just confusing me more.

Thanks
Stephen