Dual-tone multi-frequency signalling (DTMF) is an in-band telecommunication signalling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centres. DTMF was first developed in the Bell System in the United States, and became known under the trademark Touch-Tone for use in push-button telephones supplied to telephone customers, starting in 1963. DTMF is standardised by ITU-T Recommendation Q.23. It is also known in the UK as MF4.
The Touch-Tone system using a telephone keypad gradually replaced the use of rotary dial and has become the industry standard for landline and mobile service. Other multi-frequency systems are used for internal signalling within the telephone network.
The tone that is often repeated is eight notes, which has been translated numerically as "28322489." The tone was created using the audio-editing software Audacity, and the tone even translates to the sequence "AUDACITY", which is the default when generating DTMF tones in Audacity.
The investigation into the DTMF tones was prompted by the video "SFLihy," in which the DTMF tones sound like a telephone dialling. This is when fans started making connections to other videos, referring to the tone as a "melody."
Even though Meatsleep was using this code since March of 2014, it was not discovered until January of 2016. This late discovery angered Meat, and they took to Twitter to express their disappointment.
- "7 years . 6 youtubes . DTMF , the tone of words. At the end. Stupid. Stupid people takes you so long" @sewnkin on Twitter, 1 Jan 2016, 6:15 AM
Nevertheless, even though the tones have been used since the beginning, it is still unknown as the what purpose they serve to the videos, since the literal translation has no real meaning.
The following is a list of videos that feature the use of the DTMF tones:
|Title||Release Date||Usage||Time Point|
|fournine||Mar 28, 2014||First four notes opens the video||0:00|
|‡i‡n⁜g‡r‡a‡t‡e‡||Apr 4, 2014||Serves as background to the voice||0:00 (throughout)|
|新しいスキン (circle)||Apr 9, 2014||Filtered for background noise||0:03 (throughout)|
|ₛₑ⍒⎍ⓚ⑊⭔||Apr 20, 2014||Filtered for background noise||0:02 (throughout)|
|ᛊᚻ∃ᛌᛋ ᚤ ᛕ≡∄ᚹ≠ᚱ||May 3, 2014||Background to the moaning||0:00|
|FlotsamJetsamLiganDerelict||May 20, 2014||Ambient background noise||0:00 (throughout)|
|commencement||Aug 22, 2014||Plays when the image flashes||6:14; 3:30|
|jemesouviens||2014||Slowed down to the length of the video||0:00 (throughout)|
|∅ᚨ℉∡∟||Nov 1, 2014||Serves as background||0:00 (throughout)|
|🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊🌊||Oct 1, 2015||Opens the video||0:00|
|amekuluk migiallunsâtuinnalittuk||Oct 7, 2015||Background to the audio of the spectrogram||0:00 (thoughout)|
|我々は、すべての友人です。一緒に私たちが見て。我々は注意する必要があります||Oct 11, 2015||Background to the speaking voice||0:00 (throughout)|
|9grouse再発||Dec 16, 2015||Ambient background noise||0:00 (throughout)|
|210 · 37 · 53 · 7 · 11 · 23 = 495766656000||Dec 19, 2015||Only heard when the audio is sped up||0:00 (throughout)|
|SFLihy||Dec 29, 2015||Ambient noise||6:26 (throughout)|
|missing bones||Jan 2, 2016||Ambient noise||0:13 (throughout)|
|サリドマイド||Jan 5, 2016||Background noise to numbers station||0:00 (throughout)|
|tell||Jan 13, 2016||Distressed sound near the end of the video||0:57 (throughout)|
|forks||Jan 21, 2016||Ambient noise||0:17|
|No More.||Jan 23, 2016||Filtered to echo||0:33 (throughout)|