First is a SPDT switch. With two of them working together, we can control a motor to move in two different directions. So, I bought four of them to control both RA/DEC.
Next is a RJ-12 socket, this is the socket for autoguiding.
Signal from this socket will be feeded into the L298 motor kit to control the motor, actually, I can also build another hand control box with simple on/off switch with the L298 motor kit.