The momentary buttons are used to generate gates (+12V amplitude) manually.
Channel 1 has a special feature: without an external signal at the input it works like the other gates. If you insert a control signal into the input, the button acts like a mute.
Internal jumpers can be used to connect Gate 1 or Gate 3 to the gate line of the internal A-100 bus. That way the module can be used to control one or more envelope generators (e.g. ADSR A-140) that are connected to the same bus board as the A-164. The gate outputs are "smoothed" with 100nF capacitors to avoid contact bouncing. If Gate unit 1 is used to switch audio signals this capacitor should be removed as it works as a low pass filter for audio signals.
channel 1: two inputs, two outputs
channels 2 +3: two outputs
3U Eurorack module, 6HP wide, 20mm deep
Current draw 10mA