Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


Synchronizing CTP Devices Using External Clocks Overview


CTP devices can use an external clock as a reference input to the system. The reference can be input on a port or on the external reference input. You can configure and prioritize up to five references depending on the CTP model. The device automatically uses the highest priority reference available, and switches to a holdover mode if all the references are lost. The following ports can be used for reference inputs:

CTP2008, CTP20024, CTP2056: P0–P3

The CTP2000 external reference input is provide by the CLK-RTM module through a DB-25 connector.

An interface module must be present in slot one of the CTP2000 chassis to provide reference synchronization throughout the device.

You can define multiple clocks as references, each with a priority, to ensure that a reference with lower priority is available if the primary clock reference fails. The reference inputs to the CTP device must be 32 Kbps, an n x 64 Kbps (up to 4096), or 1.544 Mbps. The CTP device provides a reference holdover with an accuracy of approximately 100 parts per billion if the reference is lost and no backup is defined or available.