The tapping protocol was introduced in 19963 in order to meet a federal court's requirement that New York offer a 911 notification alternative that would "provide the hearing-impaired with a means of identifying not only their location, but also the type of emergency being reported."4 Under New York City's Enhanced 911 ("E-911") system, every telephone and emergency call box automatically transmits its location to 911 operators, so that an operator receiving a tapping call will have the caller's location on-screen and will be able to distinguish, by the tapping pattern, which emergency services are being requested.
Del Signore, John (Jan 15, 2014). "Do YOU Know The "911 Tapping Protocol"?". Gothamist. Archived from the original on 2018-02-25. Retrieved 17 March 2018. https://web.archive.org/web/20180225073442/http://gothamist.com/2014/01/15/911_tapping_protocol.php ↩
"How to Call for Help in an Emergency for the Deaf & Hard of Hearing, Tapping protocol (CC)" (video). New York City Fire Department (FDNY). 20 January 2011. Retrieved 17 March 2018. https://www.youtube.com/watch?v=qQD0uDz5gVM ↩
Civic Association of the Deaf v. Giuliani, 970 F. Supp. 352, 357 (S.D.N.Y. 1997) ↩
Civic Association of the Deaf v. Giuliani, 915 F. Supp. 622, 638 (S.D.N.Y. 1996) ↩