| 摘要 |
<p>PURPOSE:To normally execute the backup operation of call originating operation or call terminating operation, etc., by switching automatically a faulty leased circuit to a public network to be used as the backup of the leased circuit at the interface part of communication equipment after the fault of the leased circuit is detected. CONSTITUTION:A circuit state at the leased circuit interface 1 is supervised, and when the fault occurs in the leased circuit, the counting of fault occurring time is started, and after confirming that the fault continues for definite time (for instance, 30sec), a circuit switching part 3 is controlled so as to be switched to a public circuit interface 2. A circuit switching control part 6 supervises the circuit state at the leased circuit interface 1, and when it confirms that the leased circuit is normal for the definite time (for instance, 1min) while no call originating operation or no call terminating operation is executed, it controls the circuit switching part 3 so as to be switched to the leased circuit interface 1.</p> |
