In 1950, when this film was made, “long distance direct dialing” meant the ability of long distance operators to directly dial a number, with crossbar switches setting up all of the intermediate circuits automatically. Subscribers still had to call a long distance operator to initiate the call, but the connection was set up dramatically faster with less human intervention in the process.
Direct distance dialing by telephone subscribers, without any operator assistance, was first demonstrated in 1951 and rolled out slowly through the 1950s, then widely in the 1960s. Widespread international direct distance dialing was not introduced until 1970.