Dual purpose printer interface device capable of connecting a printer and a joystick to a portable host computer

A dual purpose primer interface device capable of connecting a printer and a joystick to a portable host computer, said printer interface device comprising:

• a printer connector to be connected to said printer;
• a printer interface circuit connected to said printer connector and said host computer, said printer interface circuit being capable of transmitting printer data and control signals from said host computer to said printer via said printer connector and being capable of transmitting printer status signals from said printer to said host computer via said printer connector;
• an adaptor for removably connecting said joystick to said printer connector;
• a joystick interface circuit connected to said host computer and said printer connector, said joystick interface circuit being capable of transmitting joystick signals from said joystick to said host computer via said printer connector and said adaptor;
• a first selecting means connecting electrically said host computer to said printer interface circuit and to said joystick interface circuit, said first selecting means being operable selectively in a first mode, wherein said printer interface circuit is connected electrically to said host computer and said joystick interface circuit is disconnected from said host computer, and in a second mode, wherein said joystick interface circuit is connected electrically to said host computer and said printer interface circuit is disconnected from said host computer, said first selecting means including a first multiplexer and a switch circuit, said printer interface circuit including a printer control register, a printer data register and a printer status register, said printer control, data and status registers being connected electrically to said first multiplexer, said first multiplexer being operable to enable said host computer to transmit said printer data and control signals respectively through said printer control and data registers and to receive said printer status signals from said printer status register when said first selecting means is in said first mode, said joystick interface circuit being connected electrically to said switch circuit which is operable to connect electrically said joystick interface circuit to said host computer when said first selecting means is in said second mode;
• and
• a second selecting means connecting electrically said printer connector to said printer interface circuit and to said joystick interface circuit, said second selecting means being operable to connect electrically said printer interface circuit to said printer connector and to disconnect said joystick interface circuit from said printer connector when said first selecting means is operated in said first mode and to connect electrically said joystick interface circuit to said printer connector and to disconnect said printer interface circuit from said printer connector when said first selecting means is operated in said second mode.