| 摘要 |
<p>When a call control unit (11 (12)) in operation is not carrying out call processing during system change for management, it changes its operating mode to a stand-by mode; when it is carrying out a call processing during system change for management, it changes its operating mode to a transitional operating mode to continue the call processing. When the operating mode of a call control unit (11(12)) changes to a stand-by mode, the other call control unit (12(11)) changes its stand-by mode to an operating mode; when the operating mode of the call control unit (11(12)) changes to a transitional operating mode, the other call control unit (12(11)) changes its stand-by mode to a transitional operating mode. Upon receiving a new call control signal of a call, either of the call control units (11, 12) in transitional operating mode exclusively carries out the call processing of the new call.</p> |
