Telecommunication
The conventional telephone was invented independently by Alexander Bell and Elisha Gray in 1876. Antonio Meucci invented the first device that allowed the electrical transmission of voice over a line in 1849. However Meucci's device was of little practical value because it relied upon the electrophonic effect and thus required users to place the receiver in their mouth to "hear" what was being said. The first commercial telephone services were set-up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London.
Martin Cooper (inventor)
While at Motorola in the 1970s, Cooper invented the first handheld cellular mobile phone (distinct from the car phone) in 1973 and led the team that developed it and brought it to market in 1983. He is considered the "father of the (handheld) cell phone" and is also cited as the first person in history to make a handheld cellular phone call in public.