Visual, auditory and ancillary methods (non-electrical) :

Prehistoric: Fires, Beacons, Smoke signals, Communication drums, Horns
6th century BCE: Mail
5th century BCE: Pigeon post
4th century BCE: Hydraulic semaphores
1500 Korean hwacha net uses hwachas arrows to send mails throughout a town.
15th century CE: Maritime flag semaphores
1672: First experimental acoustic (mechanical) telephone
1790: Semaphore lines (optical telegraphs)
1867: Signal lamps
1877: Acoustic phonograph
Basic electrical signals Edit
1838: Electrical telegraph.
1830s: Beginning of attempts to develop "wireless telegraphy", systems using some form of ground, water, air or other media for conduction to eliminate the need for conducting wires.
1858: First trans-Atlantic telegraph cable
1876: Telephone. See: Invention of the telephone, History of the telephone,
1880: Telephony via lightbeam photophones.

Advanced electrical and electronic signals :

1896: First practical wireless telegraphy systems based on Radio. See: History of radio.
1914: First North American transcontinental telephone calling
1927: Television. See: History of television
1927: First commercial radio-telephone service, U.K.–U.S.
1930: First experimental videophones
1934: First commercial radio-telephone service, U.S.–Japan
1936: World's first public videophone network
1946: Limited capacity Mobile Telephone Service for automobiles
1956: Transatlantic telephone cable
1962: Commercial telecommunications satellite
1964: Fiber optical telecommunications
1965: First North American public videophone network
1969: Computer networking
1973: First modern-era mobile (cellular) phone
1979: INMARSAT ship-to-shore satellite communications
1981: First mobile (cellular) phone network
1982: SMTP email
1983: Internet. See: History of Internet
1998: Mobile satellite hand-held phones
2003: VoIP Internet Telephony

Thanks for reading.