← Back to hardware

Bidirectional Logic Level Shifter (3.3V ↔ 5V)

A bidirectional level shifter translates between the Raspberry Pi's 3.3V GPIO and 5V logic found on some radio control/COS lines and accessory boards. Why it matters: Pi GPIO is NOT 5V tolerant — feeding a 5V COS/busy signal straight into a Pi input can damage it. A level shifter (or at minimum a resistor divider / opto on inputs) protects the node computer and keeps logic levels clean in both directions. Use: Place between Pi GPIO and any 5V logic line for COS sense or PTT/control. Not needed when your interface already conditions levels (most CM119 adapters do).