| 摘要 |
PURPOSE:To simplify clock circuits, to relieve the load of software and to reduce power consumption for circuits not is use by controlling a reset signal to an interface circuit of each connecting port, a reception input signal and an interruption signal to a control circuit in response to the state of switching of the test/telephone mode to use an output of a digital synchronizing circuit as a master clock of the test equipment. CONSTITUTION:In connecting a changeover switch 6 to the position of the upper power supply Vcc, the titled equipment acts like a digital telephone set. In connecting the switch 6 to the position of the lower side ground, a signal control section 4 discriminated that a command comes while functioning the equipment as a test equipment, a signal corresponding to a signal '0' is fed to a telephone mode signal line 17, a selector 5 selects an interruption signal IRQ1 and an AND gate 11 blocks a signal entering an interface circuit 9 from a connection port 10. An interface circuit 8 and an input/output section 3 are observed from the signal control section 4 and an interface circuit 9 is not observed therefrom, then a subscriber's equipment such as a digital telephone set is connected to a test connecting port 7 to conduct a test.
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