Editing Digital multiplex hierarchy

In [[telecommunications]], a '''digital multiplex hierarchy''' is a hierarchy consisting of an ordered repetition of [[tandem]] [[digital multiplexer]]s that produce signals of successively higher [[data]] rates at each level of the hierarchy.<ref name="Weik 2000">{{cite book|title=Computer Science and Communications Dictionary|publisher=[[Springer Publishing]]|location=[[Boston]], [[United States]]|isbn=978-0-387-33556-8|doi=10.1007/1-4020-0613-6|url=https://link.springer.com/referencework/10.1007/1-4020-0613-6|first=Martin H.|last=Weik|chapter=digital multiplex hierarchy|year=2000|s2cid=38594618 }}</ref><ref>{{cite journal|title=8 - Digital transmission hierarchies|journal=Digital Signal Transmission|publisher=[[Cambridge University Press]]|year=1992|first1=Chris|last1=Bissell|first2=David|last2=Chapman|doi=10.1017/CBO9781139172547.012|pages=263–285|isbn=9780521415378 |url=https://www.cambridge.org/core/books/abs/digital-signal-transmission/digital-transmission-hierarchies/57DB5A7D8CE85189525BE385B6345490}}</ref>

Digital [[multiplexing]] hierarchies may be implemented in many different configurations depending on; (a) the number of channels desired, (b) the [[Signaling (telecommunications)|signaling]] [[system]] to be used, and (c) the [[bit rate]] allowed by the [[communications media]].<ref name="Weik 2000" />

Some currently available digital multiplexers have been designated as [[Digital Signal Designation|Dl-, DS-, or M-series]], all of which operate at [[T-carrier]] rates.<ref name="Weik 2000" />

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 data|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 (electrical engineering)|line]] rate (2 digroups plus overhead bits) is 1.544&nbsp;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&nbsp;Mbit/s, supporting 30 voice channels or their equivalent in other services.

==See also==
* [[Digital transmission hierarchy (disambiguation)|Digital transmission hierarchy]]
* [[Plesiochronous digital hierarchy]]
* [[Synchronous digital hierarchy]]
* [[Transmission (telecommunications)]]

==References==
{{Reflist}}
*{{FS1037C MS188}}

[[Category:Multiplexing]]

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