The abbreviation DTMF stands for Dual Tone Multiple-Frequency, also called Touch Tone. This can be a code that is used to send information with radio och phone. The prestigious American company Bell Labs that is owned by Nokia is the developer of DTMF.

The tones you hear when pressing buttons on a phone, it DTMF. Every click sends two tones on two different frequencies.Every number have their own, predestined frequencies. Number 1 consists of the tones 697 and 1209 Hz for example. The system has also proved reliability.

DTMF came to the US in the 1940s as a streamline of a system for telephony that then was built on the impulse system, with a rotary dial. Many that grew up in the 1970s or earlier are used to phones with rotary dials which were much more ineffective to call with.

  • DTMF is a way to send information over vast distances
  • The US based company Bell Labs invented the technique
  • DTMF technique isn’t interruption sensitive and is considered reliable
  • DTMF is a standard in phone telephony companies
  • The previous system was phones with rotary dials
  • Every number is coded with 2 tones on predestined frequencies
  • Number recognition technique is excepted to be the next big breakthrough in the field

Bell Labs – The pioneer in telecommunication

Bell Labs is an American research company in telecommunication and is owned by Nokia, hence the new name “Nokia Bell Labs”. The company was founded in 1925 and is associated with the progress in information technology and telecommunication.

DTMF set a completely new standard in telephony and was a huge breakthrough. The Touch Tone phones became a necessity in industrially developed countries. The earlier system didn’t have tones, the numbers instead corresponded a number of pulses and took longer to dial.

DTMF is just one of many Bell Lab’s inventions. This research company has also contributed with important progress in sun-cell technology, transistor technology and program language. They also invented the operating system Unix and the first 32-bit micro processor (BELLMAC-32A). It’s interesting to see that the successful company now remains in nordic possession through Nokia.

The future of DTMF

The Touch Tone function is something you need to activate in modern mobile phones and you can in general call without it. In december 2010, most companies began replacing DTMF with voice recognition, and it’s safe to assume that in the long run it will be completely replaced by new systems.

Before there was a close connection between DTMF and radio, but even radio is merging over to web-based solutions that don’t require Touch Tone. However, it’s important to note that DTMF is a system that has been in use for a long time despite of how fast new technique is developed today.

Voice recognition is built on the fundamental idea that phones and computers learn to understand human language. Instead of sending tones we just have to say the numbers out loud instead. However, Touch Tone  isn’t completely out of the game quite yet, it will be around for a while.