Sony MAVE-F555 Operation Manual page 147

Using the TO MAV (PARALLEL I/O) connector of the MAVE-F555, and
connecting multiple MAVE-F555 units to a single MAV-555, you can
easily control different ports of the MAV-555 from the MAVE-F555 units.
For example, when the MAV-555 is in the 1 IN/3 OUT configuration,
while using the MAV-555 for recording from a line, you can configure a
distribution system, with the three ports P1 to P3 subject to file assignment
and control from respective MAVE-F555 units.
4-1 (E)
Chapter 4 Operations When Multiple MAVE-F555 Units Are Connected to the MAV-555