Real 737 Start Switches

This page is under construction and information is not yet final. (Thus changes may apply as I continue to test and implement).


The switch is build up out of 3 parts.

  • X1 and X2
  • A1 to A5
  • B1 to B5

X1 and X2 are used to power the solenoid, which is interfaced through the FDS-SYS-R1X Relay Board, where X1 is + and X2 is GND. the DC (Direct Current) used is 12 volt. This switch can be used between 12V and 28V DC, and uses about 10mA (120mW-280mW). The connections A1 to A5 are the positive and B1 to B5 are the GNDs. Note that there are 5 connections possible, whereas there are only 4 positions. The rotary switch operates under a push/turn mechanism. The "Off" position is the tricky one. None of the connections are active when it is in the "Off" position. Therefore we need to trigger this position as inverted. In InterfaceIt this means that On/Down = Off and Off/Up = On.

Since the position A5-B5 is active when the switch is in GRD or CONT position and A4-B4 in FLT position, a bridge is needed between A4 and A5 so that InterfaceIT knows at all times that the "Off" position is not selected.

Connection layout:

  • A1-B1: GRD
  • A2-B2: Cont
  • A3-B3: Flt
  • A4-B4: Off (Inverted) at FLT condition
  • A5-B5: Off (Inverted) at GRD and CONT Condition.

Custom XML Files will be created and listed in the Files section shortly.