An apparatus is described having an electrical interface that supports a first specification and a second specification. The first specification specifies differentially transmitted data. The second specification specifies at least three transmitted data signals. The electrical interface includes a plurality of modular transmitter circuits where each transmitter circuit includes a single ended driver and a select circuit. The select circuit is to select either one end of a differential signal associated with the first specification or one of the at least three transmitted data signals associated with the second specification.