disconnect (HDLC) (DISC)
Disconnect (DISC) is a command from the HDLC protocol that is transmitted in Unnumbered Frames(U-Frame) and with which the connection is terminated.
A DISC command is followed by an Unnumbered Acknowledgement( UA) as a response. A new connection can only be established via Set Asynchronous Balanced Mode( SABM).
A DISC command may be sent at any time by either of the two communication partners of an HDLC connection. This command is used to transfer existing data connections of the link layer from Asynchronous Balanced Mode( ABM) to Asynchronous Disconnect Mode( ADM).