| Description | A count of Protection Switch Byte Failure conditions.
This condition occurs when either an inconsistent APS
byte or an invalid code is detected. An inconsistent APS
byte occurs when no three consecutive K1 bytes of the last
12 successive frames are identical, starting with the last
frame containing a previously consistent byte. An invalid
code occurs when the incoming K1 byte contains an unused
code or a code irrelevant for the specific switching
operation (e.g., Reverse Request while no switching request
is outstanding) in three consecutive frames. An invalid code
also occurs when the incoming K1 byte contains an invalid
channel number in three consecutive frames.
Discontinuities in the value of this counter can occur at
re-initialization of the management system, and at other
times as indicated by the value of
apsStatusDiscontinuityTime. |