A control command controls the APS operation.
(1) Lockout a Working Channel - Prevents the specified working channel
from switching to the protection line.
(2) Clear Lockout-a-Working-Channel - Clears the Lockout a
Working Channel command for the specified channel.
Reading this variable always returns zero (0).
This variable is not provided if the channels's
GroupArchitecture is onePlusOne(1).