The interface is configured as a DCE device.
When the interface is functioning as a DCE device
The command is: clock rate 56000 So it will appear on the command line interface as: Router(config-if)# clock rate 56000 Reference: Networking by Jeffrey Beasley Chapter 6 page 216.
router> enablerouter# configure terminalrouter(config) interface serial (interface number)router(config-if) no shutdownrouter(config-if) endrouter#substitute (interface number) for the actual int number.. eg serial 0/1you can find the number of the interface by using show interfaces from privileged mode
admin down basically means that an adminstrator shutdown the interface for any number of reasons, and if the admin wanted to, they could bring it back up with the 'no shutdown' command.
To configure the clock rate for the hardware connections on serial interfaces such as network interface modules (NIMs) and interface processors to an acceptable bit rate, use the clock rate interface configuration command. Use the no form of this command to remove the clock rate if you change the interface from a DCE to a DTE device. Using the no form of this command on a DCE interface sets the clock rate to the hardware-dependent default value.
HDLC
It would connect to the serial port interface of a router.
serial interface
show invetory y
Router(config-if)#no frame-relay lmi-type cisco
a serial interface on a router is basically used for WAN communications. we generally connect to other routers through internet using serial interface. In a lab scenario we generally emulate WAN connections by connecting the serial interfaces of the routers using a cable called DCE/DTE cable.
encapsulation hdlc