This BITS-valued object reports the current state of this specific channel as a set of independent flags: lockedOut (meaning either this working channel specifically can't switch to protection, or if applied to the null/protection channel, that no working channel is currently allowed to switch to it at all), sd (a signal degrade condition is presently in effect), sf (a signal failure condition is presently in effect), and switched (this channel is currently switched onto the protection line). Because these are independent bits, a channel can show multiple simultaneously -- for instance sf and switched together would mean this channel both has an active signal failure and has already successfully switched to protection because of it. For example, a channel showing only sd set without switched would mean the line is degrading but hasn't crossed the more severe threshold needed to trigger an actual protection switch yet.