Set the Master Clock

This feature is available on Passport 4460 units running software release 4.1.2 or higher. To determine if this feature is available on your Passport 4460 unit, select Attributes, and Unit Hardware. You will see the Unit Hardware window:

If Master Clock is supported on your Passport 4460, Supported will be displayed in the Master Clock field.

Each of the digital interfaces on a Passport 4460 unit uses timing signals to control the speed with which data are transmitted over communication links. Every WAN module and expansion module on a Passport 4460 (with the exception of analog voice modules) includes an oscillator that supplies a local clock signal. However, some types of network transmission (video and fax) require a single clock source to ensure synchronization of data transmissions across interfaces. The Master Clock feature provides this clock synchronization.

Use the Configurator procedure below to set the Master Clock.

Select Configure, System, and Master Clock.

You will see the Master Clock window:

This window displays the current configured interface and allows you to designate the Master Clock source.

Use the pull down menu to select the desired clock source.

If you do not want to designate a master clock for the Passport 4460 unit, select Internal. If you wish to designate a master clock for the Passport 4460 unit the select one of the listed ports. As shown in the Master Clock window above, Base, Port 2 is providing the clock source to the backplane. All other ports on the unit have the option of choosing it as their clock source.

After you have made your selection, click Save. The Master Clock setting takes effect immediately. A system reset is not required.

Continue on to Configure the Signal Protocol and Calling Address