In an independent development, Donald Davies at the UK National Physical Laboratory developed the concept of packet switching in the early 1960s, first giving a talk on the subject in 1965, after which the teams in the new field from two sides of the Atlantic ocean first became acquainted. It was actually Davies' coinage of the wording packet and packet switching that was adopted as the standard terminology. Davies also built a packet-switched network in the UK, called the Mark I in 1970.[7] Bolt, Beranek & Newman (BBN), the private contractors for ARPANET, set out to create a separate commercial version after establishing "value added carriers" was legalized in the U.S.[8] The network they established was called Telenet and began operation in 1975, installing free public dial-up access in cities throughout the U.S. Telenet was the first packet-switching network open to the general public.[9]