COCOT stands for customer-owned coin-operated telephone. These are private payphones bought by businesses, like restaurants or gas stations, rather than being installed and maintained by the local telephone company. The owner keeps the coin revenue but pays standard business line rates to the telco. They require special internal circuitry to calculate tariffs and control the coin relay mechanism.
The diner wants to rip out their COCOT because it barely makes enough quarters to cover the monthly line charge.
Related terms
POTS
Plain old telephone service is the traditional analog voice transmission network using copper wires.
PSTN
The global infrastructure of circuit-switched telephone networks operated by national and regional carriers.
Local loop
The physical wiring connecting a customer premises to the nearest telephone exchange.