The public switched telephone network ( PSTN ) is the aggregate of the world 's circuit-switched telephone networks that are operated by national , regional , or local telephony operators , providing infrastructure and services for public telecommunication . A telephone , or phone , is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly . `` Telephone '' is a song recorded by American singer Lady Gaga for her third EP , The Fame Monster ( 2009 ) . The song was written by Gaga , Rodney Jerkins , LaShawn Daniels , Lazonate Franklin and Beyoncé . It was Grammy-nominated for Best Pop Collaboration with Vocals in 2011 .
Telephone consists of an holiday.