Described herein are systems and methods of receiving first and second input signals at a first two-input comparator, responsively generating a first subchannel output, receiving third and fourth input signals at a second two-input comparator, responsively generating a second subchannel output, receiving the first, second, third, and fourth input signals at a third multi-input comparator, responsively generating a third subchannel output representing a comparison of an average of the first and second input signals to an average of the third and fourth input signals, configuring a first data detector connected to the second subchannel output and a second data detector connected to the third subchannel output according to a legacy mode of operation and a P4 mode of operation.