This object identifies the ABCD signaling bits
defined by user, and downloaded to DSP signaling
channel.
This pattern is derived from the actions specified in
'cvcmCasABitAction', 'cvcmCasBBitAction', 'cvcmCasCBitAction'
and 'cvcmCasDBitAction'.
The same pattern can map to different
cvcmABCDIncomingPattern depending on the set of actions.
This pattern is mapped to input ABCD bit pattern
received and reported to the TDM or network side.