TELEPHONE CARRIER SYSTEMS, TELEGRAPH CARRIER SYSTEMS, CARRIER TELEPHONE SYSTEMS FOR OPEN WIRE LINES, CARRIER TELEPHONE SYSTEMS FOR RADIO USE, CARRIER TELEPHONE SYSTEMS FOR CABLE USE, CARRIER TELEGRAPH SYSTEMS FOR WIRE USE, CARRIER TELEGRAPH SYSTEMS FOR RADIO USE, TELEGRAPH TRANSMITTERS, TELEGRAPH RECEIVERS, REPEATERS, REPEATER PANELS, OSCILLATORS, OSCILLATOR COILS, OSCILLATOR PANELS, FILTERS, FILTER ASSEMBLIES, TRANSMITTERS, DELAY LINES, ARTIFICIAL LINES, LINE FILTERS, CONDENSERS, TRANSFORMER...