Electrician and Mechanic, July, 1906, page 10:

Another  Selective  Wireless

    Copenhagen, May 28--"I have conquered the difficulty which has so seriously hampered other wireless telegraph systems -- the liability of messages being read by others than those for whom they are intended," Waldemar Poulsen, the inventor of the telegraphone, said yesterday.
    "My invention is entirely new and independent of all previous known spark telegraphs which have earned for Marconi and others much fame. Not only is it new, but it has great advantages over the spark telegraph. My system will allow of a very large number of stations, several hundred, working simultaneously two and two, without in the least disturbing each other. All the ships of a big fleet may communicate with each of the others without causing confusion.
    The secret of my system lies in the generating of a new kind of electric waves in which the isolated impulses are of the same shape and size, forming a continuous chain. In other words, I have generated the electric ray for which scientists have long been seeking. My appliances are simple, and the sender's consumption of electrical energy is, if anything, smaller than with the spark telegraph. I can telegraph 190 miles overland with an energy of 1200 volts, which corresponds with one and one-half horse-power."
    For a long time Mr. Poulsen has given his whole mind to physical research and experiments, and though only thirty-six years old, he has already for several years had an established reputation as one of the notable inventors of the time. The telegraphone made him famous. It is a recorder of telegraphic conversation, its principle resting upon special electro-magnetic phenomena. It has nothing in common with the Edison mechanical phonograph. Mr. Poulsen's latest invention, his wireless telegraph, seems destined to make his name still more widely known.