Digital multiplex hierarchy
In telecommunications, a digital multiplex hierarchy is a hierarchy consisting of an ordered repetition of tandem digital multiplexers that produce signals of successively higher data rates at each level of the hierarchy.[1][2]
Digital multiplexing hierarchies may be implemented in many different configurations depending on; (a) the number of channels desired, (b) the signaling system to be used, and (c) the bit rate allowed by the communications media.[1]
Some currently available digital multiplexers have been designated as Dl-, DS-, or M-series, all of which operate at T-carrier rates.[1]
In the design of digital multiplex hierarchies, care must be exercised to ensure interoperability of the multiplexers used in the hierarchy.
Digroup
Digroup is an abbreviation for digital group. In telephony, a basic group in the digital multiplex hierarchy.
In the North American and Japanese T-carrier digital hierarchies, each digroup supports 12 PCM voice channels or their equivalent in other services. The DS1 line rate (2 digroups plus overhead bits) is 1.544 Mbit/s, supporting 24 voice channels or their equivalent in other services.
In the E-carrier European hierarchy, each digroup supports 15 PCM channels or their equivalent in other services. The DS1 line rate (2 digroups plus overhead bits) is 2.048 Mbit/s, supporting 30 voice channels or their equivalent in other services.
References
- Weik, Martin H. (2000). "digital multiplex hierarchy". Computer Science and Communications Dictionary. Boston, United States: Springer Publishing. doi:10.1007/1-4020-0613-6. ISBN 978-0-387-33556-8. S2CID 38594618.
- Bissell, Chris; Chapman, David (5 June 2012). "8 - Digital transmission hierarchies". Digital Signal Transmission. Cambridge University Press: 263–285. doi:10.1017/CBO9781139172547.012. ISBN 9780521415378.
This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).