Synchronous transmission system with fault location function and monitoring device therefor

摘要

A synchronous transmission system is disclosed in which the transmission paths (leased lines) extend over several individual transmission systems (Sx). Monitoring devices (NIM) with access to at least one byte of the control data area are provided in synchronous transmission systems to write data into or read data out of the control data area. The monitoring devices (NIM) may thus be controlled and monitored by a signal source (S1).