synchronous digital hierarchy – a standard for multiplexed optical fibre networks which by specifying truly synchronoums digital channels, allows efficient addition and extraction of individual channels without demultiplexing an entire level of the hierarchy. It also makes specific provision for network management.
These investments would aim at the establishment of nationwide fibre-optic Synchronous Digital Hierarchy (SDH) networks, implementation of non-hierarchical networks and establishment of low and high bandwidth copper access systems.
