Tele-Communication (Telecom) Terms Glossary and Dictionary
SDH: Synchronous Data Link Hierarchy
Synchronous Data Link Hierarchy (SDH) is an European standard for data transmission over optical fiber network equivalent to SONET of North America. SDH's basic unit, the STM-1 (Synchronous Transport Module-level 1), operates at 155.52 Mbit/s. Transmission rates of up to 10 Gbit/s can be achieved in today's SDH systems and the 40 Gbit/s systems are possible. SDH systems are fully compatiable to SONET systems.