http://kottke.org/10/10/charlie-chaplins-time-traveller
Richard Wiseman agrees: http://richardwiseman.wordpress.com/2010/10/28/chaplin-time-travel-video-solved/
He thinks it is one of these: http://www.hearingaidmuseum.com/gallery/Carbon/WesternElectric/info/westelect34a.htm
Who would you talk to? No one cellphone towers, no reception, no satellites.