When a clock signal passes through 10 or more NEs, frequency offset and drift may occur. As a result, the clock signal transmitted to the downstream NE is degraded. To prevent this from happening, a 2M phase-locked source must be used to optimize the clock signal.
In the case of forced shutdown of the output of the external clock, the 2 Mbit/s and 2 MHz of the two external clocks are shut down and there is no output signal from the two clocks. This command has a higher shutdown priority than all automatic shutdown functions provided by software. By default, the forced shutdown of the external clock output is disabled.