Since the 155 mbs connections of coaxial cables or tail optical fibers are most vulnerable to faults in channels and are not able to provide sdh self - healing protection , we should pay special attention to its safety 由于155mbits的同軸電纜或光尾纖連接,是通路中的故障多發(fā)點(diǎn),也是不能提供sdh自愈環(huán)保護(hù)的地方。因此,要特別注意其安全問題。