In the event of planned work which results in the complete or partial interruption in a transmission system, efforts are at first made to reroute the telecommunication traffic as required.

• 为了计划工作可在相关业务具有最小损失时完成，要求传输系统计划停机。所有非针对故障的测试、测量、重新安排等（而是事先安排的）都认为是计划工作。