| 摘要 |
PURPOSE:To facilitate the maintenance, by performing the self-diagnosis in response to the off-hook, and informing a fault automatically to a prescribed area in accordance with the type of the fault. CONSTITUTION:A public telephone set consists of a telephone circuit part 10, a control part 20 and a coin processing part 30. In the case of an off-hook or detachment of a cashbox, a relay control circuit 50 actuates a contact gs in response to the actuation of a hook switch 40 or a cashbox switch 100. As a result, a DC loop is closed to a trunk line. At the same time, a CPU22 works to check the normal state of the trunk line. In addition, an inspection is given to the data on the coin collecting state of the cashbox which is stored in an RAM24. Thus a self-diagnosis is performed. If any item of diagnosis is not normal, this fault is displayed at a display circuit 60. Then the CPU22 opens a loop by controlling a forcible cut-off circuit 14 and then closes the loop again to give a dial transmission to the area to be informed in response to the type of the fault. |
