Article View: sci.electronics
Article #14802Re: Tone frequencies on telephone
From: Thomas David Kehoe
Date: Thu, 19 Nov 1992 17:46
Date: Thu, 19 Nov 1992 17:46
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1156 bytes
>or the USA equivalent should be easily obtainable. Basically, each >digit (as well as the * and # functions) are composed of 2 frequencies >sounded together. All keys in the same Column share the same lower tone >(with the lower tone ascending across columns) ... and similarly for the >rows. Which means that there are 16 tones available on a keypad, although telephones have only 12 keys. You could easily build a keypad with 0-9, #, *, and A-D. What you'd do with the A-D keys I don't know... -- "Why my thoughts are my own, when they are in, but when they are out they are another's." - Susannah Martin, hanged for witchcraft, 1692. Thomas David Kehoe kehoe@netcom.com (408) 354-5926
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Newsgroups: sci.electronics Path: arc1-ca.pugleaf.net!sparky!uunet!gumby!wupost!csus.edu!netcom.com!kehoe From: kehoe@netcom.com (Thomas David Kehoe) Subject: Re: Tone frequencies on telephone Message-ID: <1992Nov19.174629.2336@netcom.com> Organization: Netcom - Online Communication Services (408 241-9760 guest) References: <1992Nov17.075719.23612@riacs.edu> <1eg588INNs78@uniwa.uwa.edu.au> Date: Thu, 19 Nov 1992 17:46:29 GMT Lines: 14