Short for Synchronous Digital Hierarchy, an international standard for synchronous data transmission over fiber optic cables. The North American equivalent of SDH is SONET.
SDH defines a standard rate of transmission at 155.52 Mbps, which is referred to as STS-3 at the electrical level and STM-1 for SDH. STM-1 is equivalent to SONET's Optical Carrier (OC) levels -3.
SDH/SONET Tutorial A short tutorial on SDH and SONET from Queen's University of Belfast.
Transmission systems and SDH Contains links to four chapters that explain synchronous transmission, digital transmission systems, the origins and principles of SDH, and synchronous operation.
