You can use discrete transistors or transistor arrays for driving the 9V dip switch inputs, provided their other leg is connected to ground. Otherwise you'll have to use opto couplers, for switches to other signal lines.
You can use discrete transistors or transistor arrays for driving the 9V dip switch inputs, provided their other leg is connected to ground. Otherwise you'll have to use opto couplers, for switches to other signal lines.