The most common type is the 4-strand 2 twisted pair. Remember that in order to reduce the work and materials, you may run 2 or more lines within 1 wire.
Thats exactly what I need. I am working on hooking it up to an arduino project, and I was able to get the dial and hook switches figured out pretty easily. Second, you can buy modular jacks either with or without the wiring block this is the heavy plastic piece which you mount to the wall, with screws to attach the wires to; see the picture higher up on the page. In the store, it's hard to tell from outside the sealed package whether the block is included. They have probably left you either a punchdown block or a network interface box. You could probably get away with using a single switching transistor to drive the secondary from your 5VDC supply, but be sure to put a fly-back diode across the coil to keep the transistor from getting killed.