Module A-164-1 is equipped with 3 push buttons that are used to generate three separate manual gate signals (i.e. ~ +12V voltage output while button is operated, 0V when released).
The gate number (1, 2, 3) is milled into the caps and white inked. Gate 1 is a bit different: provided that no plug is connected to the input socket it behaves like the other two manual gates (the socket is normalled to +12V via a protection resistor). If a control signal (e.g. rectangle output of an LFO) is fed into the input socket the gate button 1 is working as a momentary on/off switch that is used to turn the signal on/off that appears at the two output sockets (kind of mute function). Each Gate output has two sockets available (miniature multiple).
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.
Remark for A-164-1 users: There are two angled pin headers (labelled JP2 and JP3) on the pc board. JP2 is near the bus connector, JP3 is about in the middle of the board. These are used to connect Gate 1 (JP3) or Gate 3 (JP2) to the Gate line of the A-100 bus. Only one of the two jumpers is allowed !
Attention: The module comes with a jumper installed to JP2 (i,e. Gate 3 is connected to the A-100 bus). The jumper has to be removed if e.g. an A-190 is already connected to the Gate line of the same bus board! If the A-164-1 should be used as Gate source for the A-100 bus the connection of any other Gate source (e.g. A-190) has to be removed. Otherwise a short circuit is made between the outputs of the Gate transmitters !