Problem with black burst on MUX-22s

On Optocore devices, the clock source may be internal or external.  If the source is set to "Auto Int/BNC" and there is an interruption in the black burst signal, the black burst will automatically fail over to Internal.  Therefore, if the facility needs to use the house sync,  set the clock source to "BNC" only.  This will ensure that when signal is restored to the Optocore device, it will continue using the external sync signal.