You are so blessed to live in the same town as Tom Sybert of CJ Anderson and Company. I am confident his company can come up with a custom Car Operating Panel that will fit in with your classic Elevator while being fully functional with the latest code requirements. There are a number of options with regards to a standard or a ring down line. A Phone with out a handset really cuts down on vandalism to your elevator and does a great job. I think Tom can help you with that selection as well.
A dedicated line is required. Please think long and hard about having the phone dial to an answering service in New York or Missouri. Any time an emergency elevator phone goes to music on hold, its a bad thing. I sincerely believe a local company will work harder for you and to keep your business. http://smartelevatortech.com/RetractaLadder.htm has a great ladder for the pit of your elevator.

Respectfully,

Robert L Krieger Jr.