The MDDB and PCM multidrop bridge applications support redundant masters, where both masters listen to all traffic that is being transmitted from the slaves but only the active master broadcasts data to the slaves.
There are two modes for master redundancy:
manual (default mode)
In manual mode, if a master branch fails, the second master branch must be made active manually with the force-active command in order to receive data from the master input. The bridge always broadcasts to both master branches.
auto
In auto mode, both master branch inputs are received simultaneously. This requires the master input behavior to be similar to an RTU; that is, only the active master transmits data and the standby master transmits either all 1s (MDDB) or no data (PCM). If the bridge is in auto mode, the force-active command cannot be used.