Dr. Gray invented the early pay box and sold them to many telephone compaines. Each coin makes a distinct sound as it is deposited through the chutes. A solid brass dial Western Electric ( Bell) candlestick is part of this instrument. In the early days they were set up on the hotel front desk for guests to use. They were hidden behind the desk to prevent theft. ( They were full of coins) These pay stations were often brought to your table at up-scale dining rooms. Original keys are supplied. Extremely rare. One year limited warranty. This antique telephone is wired to work on today's modern system.