I moved this thread to the homework section where I think it belongs.
I agree with Steve: the circuit changes one code into another. You could say it decodes the input or it encodes the output.
Compare this to an interpreter who translates from one language to another:
From the vantage point of the listener, the translator decodes the unintelligible gibberish of a foreign language to his clearly structured and easily understandable mother tongue.
From the point of the speaker, the translator encodes the speakers well formed words into an utterly unintelligible code only the listener understand.
From the interpreters point of view he may code from one silly language to another, still thinking his own mother tongue is the best language on earth anyway.
