Path: utzoo!attcan!uunet!world!jon_sree From: jon_sree@world.std.com (Jon Sreekanth) Newsgroups: sci.electronics Subject: Re: Phone Dial Tones Message-ID: Date: 9 Jan 91 17:48:39 GMT References: <1991Jan9.102713.10815@bernina.ethz.ch> Sender: jon_sree@world.std.com (Jon Sreekanth) Distribution: sci Organization: The World Lines: 20 In-Reply-To: hb9zz@bernina.ethz.ch's message of 9 Jan 91 10:27:13 GMT In article <1991Jan9.102713.10815@bernina.ethz.ch> hb9zz@bernina.ethz.ch (Marco Zollinger) writes: I'm devlopping a little databank program for the atari st and need the frequecy of the dial tones and eventually the waveform. Dial tone is 350Hz and 440Hz sine waves together, at equal amplitudes (This is the so-called precise dial tone. If you're generating a dial tone, this is the way to do it. Many chips that detect dial tone simply look for energy in a broad band of frequencies : for example, the Sierra Semi 2400 baud modem looks in 300 - 660 Hz, center 480 Hz) Regards, / Jon Sreekanth Assabet Valley Microsystems Fax and PC products 346 Lincoln St #722, Marlboro, MA 01752 508-562-0722 jon_sree@world.std.com