POWER SUPPLY EQUIPMENT FOR TELEPHONE CALL SIGNAL OF ACTIVE/STANDBY TELEPHONE SET

摘要

PURPOSE:To improve the reliability of the entire system against occurrence of a fault by eliminating the need for a common control part for an active equipment and a standby equipment in the active/standby telephone set use call signal power supply equipment so as to provide a control function independently of each unit. CONSTITUTION:In the signal power supply unit comprising a microprocessor 1 including a CPU 2 and a memory circuit 3, a signal voltage generating circuit 7 converting a digital signal from the microprocessor 1 into an analog signal by a D/A converter 6 to generate a signal voltage, and a relay circuit 9 or the like supplying the output to a load, the operation as an active set or a standby set depends on an output signal from the CPU 2 to a drive circuit 8 controlling a relay circuit 10 via an interlock circuit 10. The changeover operation to the active set or the standby set is realized by a signal between input and output terminals CD between CPUs 2 of each unit, an operating condition decided by comparing and discriminating operation rules stored in advance in the memory circuit 3 and a function of the interlock circuit 10 inhibiting the simultaneous operation of the two units.