| 摘要 |
<p>A time division exchange interchanges predetermined time slots of a time division multiplexed signal and returns it to a network (1) during a loop-back test. A buffer memory (150 or 160) in a time division multiplexed trunk (120) may be used to interchange the predetermined time slots. Alternatively, the buffer memory may be provided in a return loop (21') for use during the loop-back test. Therefore, it can be determined that the received signal is sent from another exchange and the loop-back test can be performed using ordinary exchanging processing procedures.</p> |
