History of Mobile phone.

The history of mobile phones begins with early efforts to develop mobile telephony concepts using two-way radios and
continues through emergence of modern mobile phones and associated services.
Radiophones have a long and varied history going back to Reginald Fessenden's invention and shore-to-ship demonstration of radio telephony,
through the Second World War with military use of radio telephony links and civil services in the 1950s,
while hand-held mobile radio devices have been available since 1973.
Mobile phone history is often divided into generations (first, second, third and so on)
to mark significant step changes in capabilities as the technology improved over the years.