Most inputs and outputs on the Aries are differential RS422-level compatible. These include the Step input, the Direction input, the Encoder inputs (A&B), and the Encoder outputs (A, B, & Z).
It is possible, with some external wiring, to use a single-ended encoder or a single-ended step & direction source. As with any single-ended signal, this signal is susceptible to noise when NOT driven by a differential source. Thus, it is not recommended to use a single-ended source.
The analog input can be driven either single-ended or differentially with no external wiring.
The drawing below applies both to the Step and Direction inputs and the Encoder A & B inputs.