On April 3, 1973, standing on a street near the Manhattan Hilton, Mr. Cooper decided to attempt a private call before going to a press conference upstairs in the hotel. He picked up the 2-pound Motorola handset called the Dyna-Tac and pushed the "off hook" button.
The phone came alive, connecting Mr. Cooper with the base station on the roof of the Burlington Consolidated Tower (now the Alliance Capital Building) and into the land-line system. To the bewilderment of some passers-by, he dialed the number and held the phone to his ear.