根据《SDH长途光缆传输系统工程验收规范》（YD/T5044—2005），SDH光缆传输工程系统误码性能测试有如下规定：测试时间分为（）小时和15分钟两种。

本地传送网SDH传输设备维护内容有（）。

《铁路无线通信维护暂行规则》规定，接收机双工灵敏度不允许低于单工灵敏度（）。

SDH中什么是电接口？什么是光接口、S参考点、R参考点？

（）any case or suspected case of quarantinable disease，or any case of eruptive disease or any death be discovered，the local quarantine officer must be notified immediately．

Should any case or suspected case of quarantinable disease，or any case of eruptive disease or any death be discovered，the local Quarantine Officer must be（）immediately.

简述SDH传输设备维护的界限划分。

The（）enables water to be blow down or emptied from the boilerIt may be used when partially or completely emptying the boiler.

Vessels must be（）valid certificate of nationality or certificated of registry or license.

Effects which are dutiable or subject to prohibitions or restrictions should be declared in （）.

（）are liable to be stoten, pilfered or may damaged due to improper handing or stowage.

SDH传输系统的主要维护对象是（），包括再生段、复用段、高阶通道和低阶通道。