Do authors have to be politically correct in article-writing?
In the absence of a compelling reason to not use politically correct language, authors should make reasonable attempts to minimize offending readers. Given the information you provided, there does not seem to be any reason not to use master/slave. The words, and even the context, do not seem inherently offensive and have an established usage in many fields. I suggest including in your response letter a statement that you do not see the established use of master/slave to describe communication systems as being offensive, but if the editor requires a change, you will be happy to comply (assuming you are).