There is a "publication of ANSI Standard J-STD-710 Audio, Video and Control Architectural Drawing Symbols." According to the article: "This new standard defines a common set of blueprint icons that represents all facets of pre-wire and installation of electronic systems, products and devices in residential and commercial environments". http://www.cedia.net/about/press-room/press-releases
"The recently published standard is available free of charge through the CEDIA Resource Library. CEA, CEDIA and InfoComm will also soon release icons that can be used in Microsoft Visio, AutoCad, and other drawing programs." Here's the link to the pdf download (first you have to do a free sign-up if you haven't before): http://www.cedia.net/ProductCatalog/Product.aspx?ID=892 If anyone finds the CAD icons whenever available, let us know.