In [[telecommunication]], 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.
<i>Note 1:</i> 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.
<i>Note 2:</i> Some currently available digital multiplexers have been designated as Dl-, DS-, or M-series, all of which operate at [[T-carrier]] rates.
<i>Note 3:</i> In the design of digital multiplex hierarchies, care must be exercised to ensure [[interoperability]] of the multiplexers used in the hierarchy.
Source: from [[Federal Standard 1037C]] and from [[MIL-STD-188]]
