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What is a Dial Tone?

Dial tones indicate an active landline telphone. But what do you do if the that dial tone is not working?

By Joan Whetzel


Pick up the handset for any landline phone and you hear a dial tone. The telephone dial tone has been around almost since the telephone came into general use. Have you ever wondered why there is a dial tone? Or why dial tones sound different depending on where the phone is located?



Dial Tone Defined

A dial tone is defined by the New American Dictionary as a “low, steady tone in a telephone receiver indicating that a number may be dialed.” Basically, a dial tone is an indicator that a landline telephone is a working phone line. The tone stops as soon as the first number of the outgoing number has been “dialed” or pushed on the push button pad. (The terms “dial” and “dialed” refer to the older style of telephones that used a rotary dial to initiate telephone calls, before the advent of push button phones.)


History of Dial Tones initiate

In the early days of telephone service, phone calls were connected by a live operator. When the operators were replaced by the automated telephone exchange, customers became confused because they were expecting some sort of response when they picked up their phone receiver (with liver operators, no response meant that the phone line was not working). The dial tone  was created as a “live phone line” indicator beginning in the 1940s, and went into widespread use in the 1950s.


Dial Tone Sounds

Dial tones vary, depending on where the phone is located.

·         In North America, the dial tone is a “buzz” sound made of two tones – a 350Hz and440 Hz, forming the “F” note.

·         In most European countries, the dial tone consists of a single tone at 425 Hz.

·         Computer modems have a recognition factor built into them for the major dial tone standards.

·         Individual company PBX systems may a dial tone that is the same as the regular dial tone or is unique to the company’s phones. If the company dial tone is different, it is meant to indicate that the number 9 must be dialed to obtain an outside line.

·         Mobile phones don’t have dial tones. The caller simply punches in the number and hits send to initiate a call.

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