I'm looking for one or more words that generalize over both 'input' and 'output'. If I had to convey this in a phrase, I would say "values that cross a system boundary".
For context, I'm looking for a clear word for a computer program I'm writing. I have a "black box" (e.g. an algorithm or a computational model). It has inputs and outputs. I need to find a good name for a programmatic construct that includes both the inputs and outputs.
Here is an example sentence: "The ____(plural noun)____ to the car efficiency algorithm are: engine cylinder count, engine displacement, vehicle weight, and vehicle miles per gallon".