Technicolor DTMF sequences

Many videotapes duplicated at Technicolor Home Entertainment Services in Livonia, MI using industrial real-time duplicators, beginning in 1989, included a sequence of DTMF tones at the start and/or end of the tape. It is not yet known exactly what each tone in the sequences indicate, except, in the hi-fi track, there's usually a pause between the first and second tones, the second tone is always 1, the third tone is always #, and the fourth tone is always D. Occasionally, 1 was the fourth tone, with D being the fifth tone instead. These test patterns were used to provide information on settings such as format, time length, audio level balance, volume control, etc. to the duplication machines, allowing better replication. On most tapes, the tones are audible on the left channel of the hi-fi audio track. However, on some tapes, the tones are audible either on the right channel of the hi-fi track or EXCLUSIVELY on the linear audio track. The most notable tapes to use these sequences came from Walt Disney Studios Home Entertainment, the home video subsidiary of The Walt Disney Company.

For a list of tapes using variations of these sequences, see Technicolor test patterns.

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