property name for input or output

This is just a general terminology question.

We have an object which represents a "signal" which can be an input or output. We are trying to think of a name for the property which indicates this. 开发者_JAVA百科The best we have come up with is "direction", but I think there must be a better term for the "in/out-ness" of a signal?

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How about: IOSignal (or whatever the variable name casing is in your language)?