Abstract: An interface apparatus for interconnecting signal lines of a computer connector and a peripheral device connector with non-matching interconnect patterns having mismatched data lines or open inputs on handshake or control lines. A pair of conductive paths extend between the connectors, with each path interconnecting one data line of the computer connector with one data line of the peripheral connector. Lights indicate mismatched interconnection of the data lines, and a switch selectively reverses the interconnection of the data lines. Additional conductive paths extend between the connectors, each path interconnecting at least one handshake or control line of each connector with at least one handshake or control line of the other connector. Two pairs of interconnecting handshake lines are each provided with a switch in gang with the data line switch for selectively reversing their electrical interconnection.