Plesiochronous Digital Hierarchy

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Plesiochronous Digital Hierarchy

(PDH) A transmission system for voice communication using plesiochronous synchronisation.

PDH is the conventional multiplexing technology for network transmission systems. The transmitter adds dummy information bits to allow multiple channels to be bit interleaved. The receiver discards these bits once the signals have been demultiplexed.

PDH combines multiple 2 Mb/s (E1) channels in Europe and 1.544 Mb/s (DS1) channels in the US and Japan.

PDH is being replaced by SONET and other SDH (Synchronous Digital Hierarchy) schemes.
References in periodicals archive ?
introduction to the Plesiochronous Digital Hierarchy (PDH)
Nokia and Nera, both leading suppliers of wireless transmission equipment, have taken a step in closer technology co-operation by signing an agreement under which Nera will license Nokia's plesiochronous digital hierarchy (PDH) radio transmission technology.
Based on Plesiochronous Digital Hierarchy technology, these systems are designed for seamless integration into any urban environment.
Mindspeed's newly expanded OptiPHY family is complemented by optical networking transceiver and crosspoint-switch solutions across the full spectrum of OC-3 to OC-192 data rates and a family of plesiochronous digital hierarchy (PDH) to SONET/SDH broadband access multiplexer (BAM) mapper solutions.