| 摘要 |
PURPOSE:To reduce the occupation area and the number of wired lines by enabling the circuit test system of a time-division electric telephone switchboard to make circuit tests by using two make contacts and two lead-in wires only. CONSTITUTION:The circuit correspondence circuit of a time-division electronic telephone switchboard is provided with a switching circuit which has a closed circuit connecting testing equipment TSTF to a circuit without disconnecting the circuit from the circuit correspondence circuit and can connect or disconnect each circuit group LCGC containing several circuits to or from a talking-current supply circuit. To make a circuit test, the above-mentioned closed circuit and switching circuits are operated for the station-side circuit test between testing equipment TSTF and the circuit correspondence circuit and the subscriber's-side circuit test between the testing equipment and the circuit side. |
