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.
See also
- Plesiochronous digital hierarchy
- Synchronous digital hierarchy
References
- ↑ 1.0 1.1 1.2 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. https://link.springer.com/referencework/10.1007/1-4020-0613-6.
- ↑ 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. https://www.cambridge.org/core/books/abs/digital-signal-transmission/digital-transmission-hierarchies/57DB5A7D8CE85189525BE385B6345490.
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