TELECORD
TELEPHONIC SIGNAL RECORDERS FOR RECORDING THROUGH THE MEDIUM OF ELECTRICITY ON A PHONOGRAPH TELEPHONIC SIGNALS, TELEPHONIC-SIGNAL AMPLIFIERS CONSISTING OF COMPLETE UNITS FOR AMPLIFYING BY ELECTRIC POWER TELEPHONIC SIGNALS, THERMIONIC OR ELECTRON TUBES, TRANSFORMERS, LOUD SPEAKERS, TELEPHONE RECEIVERS, SOCKETS, RESISTANCES, RESISTANCE MOUNTINGS, CONDENSERS, SWITCHES, AND PARTS OF THE ABOVE
Expired · June 9, 1925 · 71215510 ·