| 摘要 |
PURPOSE:To make a subscriber test possible even in call signal transmission by providing a timer to determine a test time and a timer to designate a test item. CONSTITUTION:Clock signals from clock signal generator 13 are applied to terminal CLK of counter 11 and are counted by counter 11, and a carry is generated after t seconds. Counter 12 counts carries of terminal CLK and applies signal outputs Q0, Q1 and Q2 of 1 and 0 forms to test unit 1, and a test item and a test time are determined there by combination of signals and the output of counter 11. Then, unit 1 has a timer to count time from the break time of call signals from an exhcnage, and counter 11 starts counting CLK signals and continues this counting unit the next call signal transmission. The test for one item of unit 1 is completed for t seconds. Since this time is shorter than a carry enable signal, a margin time exists after the test completion until the next call. Thus, the time of the call signal break of the exchange is utilized to perform the subscriber test. |
