Error indicator, and data modulator-demodulator and indicating method of

Abstract

An error indicator indicates plural errors with a light emitter. A MPU checks each section in a data modulator-demodulator, and flashes an error LED at a standard cycle when any error occurs. When an user turns ON an error check key in flashing at the standard cycle, the MPU varies a flashing cycle of the error LED in accordance with the detected error. Moreover, a light emitter in a data modulator-demodulator indicates whether a remote loop back test is executed by a trigger from a self-station or from other station. The MPU lights a test LED and shifts the data modulator-demodulator to an execution state when any switch is turned ON. When any of test switches except for local digital/analog loop back test is turned ON, the MPU transmits a test command corresponding to the test switch which is turned ON to other data modulator-demodulator. The other data modulator-demodulator flashes the test LED and is shifted to the execution state corresponding to the received command.