Talk:Special information tone

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AT&T/Bellcore Standard SIT composition

I don't know if it's truly valuable to cite specifically (and only) Bellcore's SIT frequency and duration specifications from 1981 when ITU-T has a much more broadly applicable and current guideline from 1998. These are^[1]:

7.2 The special information tone has a tone period theoretically equal in length to the silent period.
Tone period – The tone period consists of three successive tone signals, each lasting for 330 ± 70 milliseconds. Between these tone signals there may be a gap of up to 30 milliseconds.
Silent period – This lasts for 1000 ± 250 milliseconds.
7.3 The frequencies used for the three tone signals are: 950 ± 50 Hz; 1400 ± 50 Hz; 1800 ± 50 Hz, sent in that order.
— Preceding unsigned comment added by 174.90.120.145 (talk) 21:06, 14 November 2017 (UTC)[reply]

References

^ http://www.itu.int/rec/T-REC-E.180-199803-I

"Out-of-service" listed at Redirects for discussion

The redirect Out-of-service has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2025 March 15 § Out of Service until a consensus is reached. ObserveOwl (talk) 13:45, 16 March 2025 (UTC)[reply]

[1] ttp://www.itu.int/rec/T-REC-E.180-199803-I

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