PDH is a system (how) the merger of high-level canal which starts from thetheory of PCM, where the channel has a very high speed. PDH itself serves as alink between the central canal (HAS) in order to transmit voice signals (voice)or data together. In the system there are four levels of PDH multiplex or Orderthat each each Ordenya have different speeds. Media used for fiber optictransmission process is having the speed and capacity of approximately 2 Mbps30 Gbps. Applications that used in the PT. TELKOM is the Relationshipbetween Central (HAS). PDH advantage of it can be either data communicationsthat can be accessed with a very high speed.