Question : Phone line over the network?

I have two buildings which are connected by a single cat 5 cable.

I have phone service in building A, but not B.  Is there a device that would allow me to plug a phone into the network, at location B and carry voice over the network to location A?

The goal is to use my phone line at both location A and location B over the network.

Thank you

Answer : Phone line over the network?

A couple of these would do the job :-
http://www.voipsupply.com/product_info.php?products_id=1646

It will plug into the analogue line and transmit the voice over the normal network to the box the other end where you can have another normal phone connected.

chilternPC is correct but I assume you are asking because you want to only have one phone number.