Stand-alone
It is called stand-alone for the mode that when two or more boards are
used synchronously, the master and the slave are used independently without
using synchronous signal lines.
Master
When two or more boards are used synchronously with Synchronous
Control Connector (SC connector), the board that outputs the signal
to synchronous signal lines is called master.
Slave
When two or more boards are used synchronously with synchronous control
connector (SC connector), the board works by inputting the trigger signal
from synchronous signal lines is called slave.