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 ?
MartisDXX A111 multiplexer provides a gateway to the backbone network by multiplexing a wide range of circuit- and packet-based services including plesiochronous digital hierarchy (PDH), ATM, IP, frame relay and digital subscriber line (xDSL).
Plesiochronous Digital Hierarchy (PDH) - The standard used for transmitting data on American T-carrier and European E-carrier systems.
According to Raman Subramanian, strategic marketing manager of EXAR's communications division, "These devices offer the greatest flexibility in terms of board space, power consumption and functionality, the XRT59L91/59V97 are an optimal solution for designers of E1 line cards for Synchronous Digital Hierarchy (SDH) and Plesiochronous Digital Hierarchy (PDH) multiplexers, respectively.
The newly enhanced and expanded OneVision suite enables integrated management of networks utilizing a variety of technologies, protocols and standards, including: Asynchronous Transfer Mode (ATM), Frame Relay, Synchronous Optical Network (SONET), Synchronous Digital Hierarchy (SDH), Plesiochronous Digital Hierarchy (PDH), Dense Wavelength Division Multiplexing (DWDM) and Internet Protocol (IP).
It also provides flow-through provisioning services through its interdomain functions, including support for diverse networking technologies such as Plesiochronous Digital Hierarchy (PDH), Synchronous Optical Network (SONET), ATM, Frame Relay and Synchronous Digital Hierarchy (SDH).
Designed predominately for IP router applications, the complete solution supports both the American and European SONET/SDH and plesiochronous digital hierarchy (PDH) standards, enabling manufacturers to develop a single software-configurable design that can be used in both U.