The BP511 single circuit beltpack has 'Mic Select' switches linked in parallel. Pressing either switch will open or close the microphone circuit. The 'Mic Select' switches glow green when activated. The BP531 includes vibrate alert.
The BP523 dual circuit beltpack has A and B 'Mic Select' switches. Pressing the respective switch will open or close that microphone circuit. The 'Mic Select' switches glow green when activated. The BP543 includes vibrate alert.
The BP525 dual circuit beltpack has A and B 'Mic Select' switches. Pressing the respective switch will open or close that microphone circuit. The 'Mic Select' switches glow green when activated.