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.
Smartphone
The first integration of data signals with telephony was conceptualized by Nikola Tesla in 1909 and pioneered by Theodore Paraskevakos beginning in 1968 with his work on transmission of electronic data through telephone lines. In 1971, while he was working with Boeing in Huntsville, Alabama, Paraskevakos demonstrated a transmitter and receiver that provided additional ways to communicate with remote equipment. This formed the original basis for what is now known as caller ID. The first caller ID equipment was installed at Peoples' Telephone Company in Leesburg, Alabama and was demonstrated to several telephone companies. The original and historic working models are still in the possession of Paraskevakos.