File:Offhook Tone.ogg

Summary
A four-second sample of the North American telephone off-hook tone, consisting of frequencies 1400 Hz, 2060 Hz, 2450 Hz, and 2600 hertz, at a cadence of 0.1s on, 0.1s off. Produced using Audacity's "Generate Tone" feature set to generate sine waves. A circuit for creating this sound is described here: http://www.theremin.us/Circuit_Library/offhook.html