This is a read-create value identifying the specific ABCD signaling bit pattern that the module expects to receive on incoming CAS signaling, against which the per-bit actions such as cvcmCasABitAction are applied. An admin configures this to define what an incoming bit pattern means before the module remaps or inverts individual bits according to the configured actions. For example, an admin matching a carrier's specific CAS signaling convention would set this pattern to the exact bit combination that carrier sends for an on-hook condition.