It's cloudy and will be cloudy for some more days. So I took out my motor controller box out for further work. Last time, I drilled four holes and fixed the buttons there. These buttons are far superior than those on the Autostar/Nexstar controller, they're great to press, and they're not likely to reduce in sensitivity over time.
Those switches are normally closed, so I connected them both to high as default to the Solarbotics L298 controller kit. Since both terminals are high and thus, no current will flow through the motor drivers. When I press either one of them, the high signal will be broken and current will flow from one direction, pressing the other button will reduce in a reversed direction. Very simple indeed.
To proceed further, I will need to buy two 3.5mm mono socket so that I can connect the L298 kits motor driver output to them. They will be controlling two motors. Since this is a DC geared motor controller kit, it's going to work as a motorized focuser control. I will need to buy a power socket so that I can give 6-20V DC to this controller to drive the focusing/autoguiding motors. Maybe I can add a rheostat before the power supply socket so that I can adjust the speed of the motor as well, but this should be the next step.
Once this is done, I shall proceed to mount the DEC motor on the TG-SP II first, and RA autoguiding motor will be next, finally, I shall add that ST4 socket to the whole controller! The current controller box might be too small to have that ST4 socket attached, but I will leave this currently.