What is a Dial Tone?
A dial tone is the signal you hear on a telephone before you dial a phone number. In most instances, the signal disappears after you dial the first number. The dial tone was widely established as telephone systems became automated, starting around 1947. Prior to that, a person had to talk with a switchboard operator in order to connect with another party. When the operator was no longer necessary, many people assumed their phone wasn’t working because they heard no sound on the line. The dial tone was created so the caller knew the phone was indeed connected and working before making the call. At home or in an office, several phones can share the same telephone line. The use of the dial tone also eliminates confusion if one party picks up the phone and the line is being used elsewhere. The early dial tone resembled a buzzing sound and was created by a motor driven machine. Today, the sound of the dial tone in North America is that of two interfering frequencies of 350 and 440 Hz (Hertz
