| 摘要 |
The tone generator generates 20 Hz ring signals in response to a subscriber's request. The control method has following seven steps. The 1st step checking the predetermined surveillance time (50 msec), the 2nd step inspecting the subscriber's port, the 3rd step producing the pulses being loaded to the RAM, the 4th step interpreting the loaded data to check the status of the ring generator, the 5th step increasing the delay time to stablize the ring signals, the 6th step loading the data stored in the RAM after the expiration of the delay time, the last 7th step sending the ring signals to the port after confirming the delay data in the RAM.
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