- * Some models have digital inputs and analog inputs. These features
- * currently are not supported in this implementation.
+ * ETH484 also has 8 digital inputs, and 4 analog inputs. Features
+ * beyond relay output are untested in this implementation.
+ *
+ * Vendor's support code for ETH8020 suggests that it has 8 digital
+ * inputs and 8 analog inputs. But that digital input supporting code
+ * could never have worked, probably wasn't tested.
+ *
+ * Digital inputs and analog inputs appear to share I/O pins. Users can
+ * read these pins either in terms of an ADC value, or can interpret
+ * them as raw digital input. While not all models with digital inputs
+ * seem to provide all of them in analog form. DI and AI channel counts
+ * may differ depending on the model.