JRC JMA-3300 Series Instruction Manual page 49

Key Operations
Press:
Hold down:
Press multiple keys: Press multiple keys simultaneously.
Turn:
Press a key, then release the key before 2 seconds elapse.
Press a key, and hold down the key for 2 seconds or more.
Turn a control in clockwise/counterclockwise direction.
Chapter 2 OPERATIONS
2.2 PANEL
2
2-3