Verizon and other regulated Bell telephone companies are radically down-sizing their payphone operations. Many phones have been pulled out of service and sold as surplus.
Here's a source of parts and an instruction manual:
http://www.payphone.com/shop/catalog/Personal_Pay_Phone-p-16186.htmlYou have a genuine "Western Electric" (a.k.a. "AT&T") payphone case. As originally shipped from the factory, you need to turn two locks at the same time to get into each section of the phone. The coinbox area is called the vault. There will be a lock on the side next to the vault door that takes a flat key similar to a safe deposit box key or a mailbox key. That lock has to be turned first. Then you stick a "T" key into the hole in the front of the vault door and turn it. the vault door then pulls straight toward you. Now you can pull the coinbox straight out. Caution the coin box may have a special lid on it. Once the coinbox is pulled out a latching mechanism triggers inside the lid that latches a lever to prevent you from pushing the coinbox back in without resetting the latch. Most people take that damn lid off and throw it away cause it's such a pain.
Now to get into the top housing you also need two keys: another flat key similar to the one that was on the side by the vault door except this lock is situated higher on the side of the phone case. Turn that lock and now you can stick a "T" key into the "T' key slot on the side of the phone. Now youcan turn the "T" key and you'll hear a big 'clunk' of the heavy steel plates unlocking. Carefully slide the upper housing (with the dial and handset) toward you and off it's track about 6 inches. Now you'll see a cable coming from the keypad and it plugs into the circuit board in the back half of the phone. Unplug that cable and you can now set the upper housing aside. The interior of the phone is now fully exposed. Be careful when sliding the upper housing away from the rest of the phone---it's heavier than it looks. If you drop this on your foot you're gonna have broken bones!
Wiring and mounting the phone is explained in the manual download at the link I provided.