Abstract: Manual insertion of hardware jumpers to configure I/O device selection and addressing is eliminated through the implementation of specialized hardware which allows for program control over several addressing paths. A register file is utilized within a programmable device to configure demultiplexers and multiplexers which map I/O address control line signals to set up various communication paths for address I/O exchanges. I/O configuration is entirely removed from add-on cards through the use of the programmable device. Accordingly, such add-on cards only require minimum circuitry, thus facilitating the use of miniature or baby cards as option cards which are much smaller than standard add-on cards.