Wireless telegraphy
（重定向自Radiotelegraph）
Wireless telegraphy is the transmission of electric telegraphy signals without wires (wirelessly). It is now used as a historical term for early radio telegraphy systems which communicated with radio waves, although when the term originated in the late 19th century it was also used for a variety of other experimental techniques for communicating telegraphically without wires, such as photoelectric and induction telegraphy.