Installation guide

Software Configuration 5-29

Additional Configuration Tasks

• Clock source operation (line or internal)

Note Always enter the clear interface command after altering the conﬁguration of an

interface, particularly after changing a time slot or CRC-4 setting.

Conﬁguring Framed and Unframed Mode for E1-G.703/G.704 Interfaces

The E1-G.703/G.704 interfaces support both framed (G.704) and unframed (G.703) modes

of operation; the default is for unframed operation. To enable framed operation, you must

specify the start and stop slots. Following is a sample display of the timeslot command with

a start slot of 1 and a stop slot of 13:

router# timeslot 1-13

Invalid combinations of start and stop slots will be ignored and the interface will be left

unchanged.

The system default is not to use time slot 16 for data. To use slot 16 for data, use the

timeslot 16 command. To restore the system default, use the no timeslot 16 command.

Conﬁguring Timing (Clock) Signals for E1-G.703/G.704 Interfaces

The E1-G.703/G.704 port operates either with an external clock signal that it recovers from

the received data stream (the default clocking) or with its own internal clock signal. To

specify the clock source, use the clock source {line | internal} command.

To change the default and use the internal clock, use the clock source internal command.

To return the interface to the default state, use the clock source line command. (You can

also negate either of these commands to change a setting; for example, the no clock source

internal command also returns the interface to the default state.) All E1-G.703/G.704

interfaces operate at a default clock rate of 2.048 Mbps; the clock rate cannot be conﬁgured.