[n86121]

I don’t think my 69 T337D AP has any external inputs for pitch etc.
Except from the artificial horizon or small control head.

It may just be an “A” model?

AP has the small control head center stack down by pilots right knee.

Control head has a heading bug there, as well as pitch / turn center and controls.
Also has an altitude HOLD switch.
Activates pressure sensor in computer to “hold” altitude
At whatever pressure altitude present when switch is flipped.

If there is a vertical interface, that would be interesting.
Not critical, but interesting.

As you know 337 so stable, barely ever use AP.