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WHAT IS PDH?

PDH (Plesiochronous digital hierarchy), synchronous digital hierarchy, is a system for transporting large amounts of data over telecommunications networks. Examples include fiber optic and microwave signals.

THE PDH SYSTEM WORKS LIKE THIS IN EUROPE;

  • The E1 signal is located in the first first part of the sequence of signals.
  • These signals in turn generate 4 low level signals.

FORMATS OF THE SIGNALS OBTAINED IN THIS WAY:

  • E2 (8.448 Mbit/s),
  • E3 (34.368 Mbit/s)
  • E4 (139.264 Mbit/s)
  • 5. seviyede E5 (565.148 Mbit/s)

but the end is not standardized. These levels are the PDH (Plesiochronous Digital Hierarchy) version of the European digital multiplexing hierarchy.

SDH standardization was developed because of the disadvantages of PDH (Plesiochronous Digital Hierarchy) systems.