This object determines which E1 Sa bit is used to transmit and receive the SSM, or Synchronization Status Message, defaulting to bit4 for E1 line type, while T1 and 2048kHz line types only allow None, and None is invalid for E1 unless QL Mode is disabled. Admins configure this to align the SSM signaling bit with what the connected clock source and downstream equipment expect, since SSM tells the network which timing sources are usable and at what quality. For example, an admin leaves bits8PortGroupSaBitDesignation at bit4 for a standard E1 BITS feed so SSM quality-level messages are correctly exchanged for automatic timing source selection.