Respuesta :
radio telegraphy
The use of radio signals to send voice and written message was discovered in the 19th century. it was necessitated by the discovery of electricity. The applications of radio signals in communications in the 21st century is of far reaching effect.
The use of radio signals to send voice and written message was discovered in the 19th century. it was necessitated by the discovery of electricity. The applications of radio signals in communications in the 21st century is of far reaching effect.
Answer:
The form of communication introduced in the 19th century that is still widely used to this day is the telegraph.
Explanation:
In 1837, photographer and painter Samuel F. B. Morse created the first telegraph, in addition to creating an alphabet to transmit the information that would later bear his name, the Morse code.
Both the device and the alphabet began to be used 7 years after its invention. The first communication was made between Washington and Baltimore, separated by only 40 miles.
Telegrams are still used mainly for important notifications since these arrive physically to the receiver.