Basic question about SPST switches

I am new to panel design and electronics in general, but I've brought myself up to speed on the basics over the last couple months. I'm thinking about getting one of the USB encoders from Desktop Aviator, but I'm trying to figure out why one would use a SPST toggle switch (not push button) with any of these. When the switch is on, it sends a pulse to the board and whatever subsequent command to FSX/FSUIPC, got it. But when the switch is off how would FSX know that I'm intending to toggle the command, since all it's doing is opening the circuit? I totally understand why a SPDT switch would work in this situation, but not SPST, however DA advertises that these boards would work great with SPST toggle switches.

 

What am I missing?

Ok, nevermind I figured it out. It turns out DA accounts for this in the programming of the board itself. I thought it was a basic circuit issue, but the board is actually programmed to send a pulse when the circuit is closed AND to send a pulse when the circuit is opened. That's all there is to it.

Correct. In flight sim most commands are click once for ON; click again for OFF. So, by pulsing whenever the physical SPST switch is moved, that satisfies the sim's requirements.

Keep in mind that with FSUIPC, you can use a SPST toggle as though it were a DPDT toggle because you have the ability to assign a key to be pressed when the "Button" is "Released". So you can actually assign commands like Landing gear down to the "Off" position of a SPST toggle. Or basically you can get a function to happen on both the on and off positions.