A community repeater is usually one repeater with a "tone panel" on it. A tone panel is a device that listens for a specific PL or DPL and, when the right one is received, turns on the transmitter and generates a PL or DPL code so that the user can communicate through the repeater. It also keeps track of how long the cumulative transmission times are on each one. Zetron, Connect Systems, Inc. (the original "CSI"), and Communications Specialists make commonly used tone panels.
The owner sells air time to one or more companies and usually either bills them a flat rate for how many radios they have, like $25 per radio per month ($25 * 100 radios = $2,500/ month revenue) or bills them for air time, like $50 per hour per month. (100 hrs for the last month * $50/ hr = $5,000 revenue for that month). Those numbers are made up.
The system works with users from other companies talking at different times. A community repeater is the precursor to trunking in that multiple users share the same radio system and not everyone talks at the same time.
If the customer doesn't pay, then the owner can turn them off and they can no longer talk to each other until they settle up and the owner turns them back on.
These were very popular in the 80's and early 90's until trunking came out and until many businesses went to Nextel. As some businesses leave Nextel, community repeaters and other modes of sharing a fixed number of channels are getting popular again.
Some people also put community repeater controllers on their GMRS and ham repeaters for various reasons.
