This Recommendation defines the DTE/DCE interface for public data networks providing frame relay data transmission service by dedicated circuit. It defines frame relay basic service for permanent virtual circuits and switched virtual circuits and frame relay link layer protocol for data transfer. It defines permanent virtual circuits management protocol and signalling for switched virtual circuits. It also defines the following network capabilities: closed user group, reverse charging, transit network selection, transfer and discard priorities and service classes, NSAP support by the network for interworking with ATM networks, multiprotocol encapsulation and selection and fragmentation at the DTE/DCE interface. This revision replaces ITU-T X.36 (1995) and its Amendments 1, 2 and 3.