Synchronous digital transmission systems based on CCITT SDH standard
Hiroyuki Kasai, Takehiro Murase, Hiromi H. Ueda · IEEE Communications Magazine · 1990
The synchronous digital hierarchy (SDH) transmission systems developed by NTT are discussed. The advantages of SDH are detailed, stressing its simplified network structure and enhanced operations, administration, and maintenance functions. The layered architecture of the SDH systems is described. NTT's SDH fiber-optic transmission systems and digital radio transmission systems are presented.>