Telephone Equipment-Namely, Key Telephone Sets, Key Telephone Sets with Called-Party Monitor Circuit, Key Telephone Sets with Busy Lamp Field, Key Service Units, Power Supplies, Intercom and Door Answering Boxes, Door Chime Boxes, Direct Station Selection Consoles, Applique Boxes, Speakerphones, Flash Switch Assemblies, Wall Mounts for Mounting Key Telephone Sets on Walls, and Parts Thereof; and Key Telephone Systems Consisting of Some or All of the Foregoing Items of Telephone Equipment