Computer system incorporating an infrared link for reduced interference

Abstract

Two units are disclosed, one of which is installed in the computer and one of which is located remotely and includes the antenna and radio frequency transmitter and receiver elements. The two units communicate over an infrared (IR) link. The data is transmitted between the two units as real and imaginary components using separate IR signals. By using real and imaginary digitized signals, great flexibility is provided as to the actual contents and protocols capable of being utilized and serial digital data can be provided from the computer and received in the computer using only simple table look-ups. The antenna unit includes personalization byway of differing filters and software to allow it to operate with a plurality of radio channels and protocols. Each unit has a serial number to identify itself and to keep a communication link secure once established. The IR link is established by hitting an initialization switch on each of the two units, at which time they commence transmitting their serial numbers and an acknowledgement process occurs. Once this initialization has occurred and both units have registered the other unit, only communications from the proper serial number provider are accepted. After the initialization phase, data and commands are sent between the two units in a packetized structure which allows error checking as necessary.