PCIe 6536b with differencial signals

I would like to use the PCIe 6536b card to read some high speed A Quad B  signals from an encoder.  The signals are differential. A+, A-,B+, B- and a differential clock signal.  I cannot find how to connect things when the signals are differential rather than single ended. Do I need additional hardware to convert to single ended signals or can the 6536b handle these signals on it's own?  Thanks