You must configure HDLC over the T3, T1, unframed E1, or fractional T1/E1 line that you configure on an interface. As Figure 8 shows, HDLC must be the top layer of the interface stack.
To configure an HDLC channel, specify a serial interface. For example:
- host1(config)#interface serial 4/0:1/1/1/1