An on board system for a taxicab having a wireless modem that allows a passenger to charge his fare by use of a credit card to a remotely located institution responsible for the charge account. The system also provides bilateral communication to allow messages to be successfully exchanged in order to successfully conduct the business of carrying passengers in the taxicab.

A taxi meter system mounted on a taxicab for accurately computing a fare for a taxicab trip as function of time and distance is disclosed. The system provides discrimination means that eliminate the contribution to the fare that may otherwise be created by illegal means that degrade the performance of the taxi meter system.

A verification and monitoring system for signal and status indicators and voice and metering features which is particularly suited for a taxi cab is disclosed. The operational status of the indicators are initially verified each time the ignition system of an associated taxi cab is energized. The verification circuit detects the failure of individual indicators even though a plurality of indicators may serve as a single visual display. The voice and metering features are continuously verified.