| Definition: | series of levels of digital multiplexing in which each level is characterized by a defined bit rate, and in which each level handles a digital signal assembled by multiplexing signals whose bit rate is that of a lower level
Note 1 to entry: The Standardization Sector of ITU has standardized two digital multiplex hierarchies, the plesiochronous digital hierarchy (PDH) and the synchronous digital hierarchy (SDH).
|