Voice traffic over Point to Point T1?

We have to office locations (A & B). Currenlty A has a Avaya phone switch. We are looking at moving people to location B and setting up a point to point T1 between the two. Data traffic will be easy, but can someone help me understand our options for voice? Currently at location A there are no direct numbers, only extensions. Ideally we would like workers at location B to have extensions and be able to transfer calls directly to extensions in our office. Can we utilize our current switch between locations using the T1?