| 摘要 |
PURPOSE:To measure a loop resistance automatically in a short time without requiring the operation of the maintenance personnel by the response of a subscriber after the subscriber callout through the operation of the maintenance personnel by operating mutually a subscriber response detecting circuit in a test device, a loop resistance measuring circuit and its control section. CONSTITUTION:In figure, 1 is a response detecting circuit monitering off-hook of a subscriber, i.e., the response, 2 is the loop resistance measuring circuit, and 3 is the control section. Suppose that a call signal is transmitted to the subscriber by the operation of the maintenance personnel. When the subscriber responds by hooking off a handset of a telephone set, a relay A in figure is operated, its contact (a) is closed so as to transmit the response of the subscriber to the control section. The control section detects the response, operates a relay MES, changes over a channel to the measuring section and transmits a start signal (ST) to the measuring section. The measuring section receives an ST signal and completes the measurement in a very short time and transmits the result of measurement (DATA) to the control section. Then, the control section restores the relay MES, and opens the channel so as to attain the communication between the subscriber and the maintenance personnel. |
