OK, one by one:

For some reason I can't find TTS-1 but I have loads of other VSTi's. Tried Kontakt5 (among others) but it doesn't work. Playback is fine, virtual keyboard is fine, no input from Impulse.

I did a full reset to Factory Settings, but no results.

Then I started up Realband and had to define my MIDI driver setup. Chose Impulse in, Control (VS-100) out and CoyoteWT as synth and then I got this:

Error opening input driver: Impulse
A non-defined external failure has occurred (I have to translate this from my Dutch OS)

Then I chose MIDIIN2 (Impulse). Same result.
Then I chose EWI-USB. Same result.
Then I chose MIDI (VS-100) and then CONTROL (VS-100) with the same results.
And then I'd run out of options.

Seems to me this is tell-tale though I'm not at all sure what tale it tells.