guidon (plural guidons) 1  A small pennant or banner carried by infantry soldiers to direct troop movement. 2  A soldier assigned to carry such a banner.
Within a year or two, Western Union and other telegraph companies were using diplex telegraphs on their busiest lines in major cities. In 1874, Thomas Edison invented the first quadruplex telegraph, which was capable of sending two messages simultaneously in each direction.ears later, quadruplex telegraphs were displaced by two new inventions, multiplex telegraphy capable of eight or more simultaneous transmissions, and the use of teletype machines, which did not require their operators to know Morse Code.
Meanwhile, Elisha Gray was also experimenting with acoustic telegraphy and thought of a way to transmit speech using a water transmitter. On February 14, 1876, Gray filed a caveat with the U.S. Patent Office for a telephone design that used a water transmitter. That same morning, Bell's lawyer filed Bell's application with the patent office. There is considerable debate about who arrived first and Gray later challenged the primacy of Bell's patent. Bell was in Boston on February 14 and did not arrive in Washington until February 26.