Automatic Protection Switching (APS) and error signal processing
coordination apparatus and methods are disclosed. If a communication
module that enables communication signals and error signals to be
exchanged with a remote communication module is configured in an APS
protection group, error signal processing by the communication module is
restricted. This prevents Time Division Multiplexing (TDM) T1/E1 Remote
Defect Indication (RDI) signal processing, for example, from interfering
with Synchronous Optical Network/Synchronous Digital Hierarchy
(SONET/SDH) unidirectional One-plus-One APS. Under certain conditions,
however, a restricted communication module may be allowed to perform a
restricted error processing operation or revert to normal unrestricted
error signal processing.