The following standards specify the interface between data terminating equipment (DTE) and data circuit-terminating equipment (DCE) for terminals operating in the packet mode on packet-switched data networks (PSDN), or between two DTEs, by dedicated circuit: (1) CCITT Recommendation X.25, interface between Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE) for Terminals Operating in the Packet Mode and Connected to Public Data Networks by Dedicated Circuit. (2) ISO 7776:1986, Information Processing Systems - Data Communication - High-Level Data Link Control Procedures - Description of the X,25 LAPB-Compatible DTE Data Link Procedures (3) ISO 8208:1987, Information Processing Systems - Data Communications - X.25 Packet Level Protocol for Data Terminal Equipment CCITT Recommendation X.25 specifies the DCE side of the DTE/DCE interface. ISO 776:1989 and ISO 8208:1987 specify the DTE/DTE interface and the DTE side of the DTE/DCE interface. This standard confirms to the requirements of the three listed in this section and covers the DTE/DCE and DTE/DTE interfaces.