PDH

PDH, or Plesiochronous Digital Hierarchy, is a telecommunications technology used to transmit large amounts of digital data over fiber or copper cables. It organizes data into multiple levels, called hierarchy tiers, allowing efficient and standardized transmission of voice, video, and internet services. "Plesiochronous" means the signals are almost synchronized but may have slight timing differences, which are managed through synchronization methods. PDH helps telecom providers handle high-capacity data flows efficiently, serving as a foundation for modern digital communication networks.