COM KEY

KEY TELEPHONE COMMUNICATION SYSTEMS-NAMELY, CUSTOMER PREMISES TELEPHONE SYSTEMS COMPRISED OF MULTILINE TELEPHONE SETS AND MISCELLANEOUS COMMON EQUIPMENT COMPRISING ATTENDANT CONSOLES, POWER SUPPLIES, CONNECTOR BLOCKS, MOUNTING PANELS, AND PLUG-IN UNITS, WHEREIN A COMMUNICATION PATH IS SELECTED BY THE USER BY DEPRESSING A BUTTON ON A MULTI-LINE TELEPHONE SET