Protocol-control information

In telecommunication, the term protocol-control information or PCI has the following meanings:

  1. The queries and replies among communications equipment to determine the respective capabilities of each end of the communications link.
  2. For layered systems, information exchanged between entities of a given layer, via the service provided by the next lower layer, to coordinate their joint operation.

Public Domain This article incorporates public domain material from the General Services Administration document: "Federal Standard 1037C".