Telephones
In the 1940s, only about 30% of rural households had telephone service. It was much more prevalent in suburban and urban communities, however. The details of dialing a number aren't important, but what is important is that for most phones, the only way to actually call anybody was to talk with an operator first. Phones didn't have their own dial device. All long distance calls had to be handled manually by an operator. By 1947, area codes were only just starting to come into service.
Telegrams
If you had an urgent message to send, a telegram was the best way to do it. You could stop by the local Western Union, or if one wasn't nearby, call one, and have your message sent over telegraph lines. By 1945, Western Union was replacing its poles and wires with microwave transmissions.