DIGITAL PRIVATE BRANCH EXCHANGES (PBXs); ROUTERS FOR DIGITAL NETWORKS; SWITCHES FOR PUBLIC OR CORPORATE NETWORKS, IN PARTICULAR PUBLIC TELEPHONE SWITCHES; NETWORK MANAGEMENT SYSTEMS; PRINTED WIRING BOARDS FOR PC AND OTHER MICROCOMPUTERS; NETWORKING BOARDS FOR PC AND OTHER MICROCOMPUTERS; VIDEO BOARDS FOR PC AND OTHER MICROCOMPUTERS; COMPUTER PROGRAMS FOR CONTROLLING PRINTED WIRING BOARDS, NETWORKING BOARDS AND VIDEO BOARDS, EACH FOR PC AND OTHER MICROCOMPUTERS; COMPUTER PROGRAMS FOR DATA COMM...