Electro-magnetic interference from an AT&T; cordless phone handset CL82301 when held near the internal Ferrite antenna on the back right of a 13-year-old boombox set to the bottom end of the AM broadcast band. Recorded with Goldwave from line-in. The recording starts with tones from the phone on standby near the radio. You hear a series of nearly pure tones. The phone comes on and you hear a distorted dial tone. Then you hear distorted dtmf tones 1 through 0, then a ring. I disconnect and the phone continues sending to the base for a few seconds so you just hear a hum, then the idle tones are heard. For some reason the tones are at a different pitch and speed on different days or at different times of the day.
AT＆T無繩電話dtmf AM Radio.wav
聲道：2
類型：wav
radio-interference、digital、dial-tone、buzz、tones、t、noise、glitch、beep、electro-magnetic、hum、dtmf、interference、distorted、EMI、pulse、electronic、am-radio、EMF、cordless-phone
無線電干擾、數字、撥號音、蜂鳴器、音、Ť、噪聲、毛刺、嘟、電磁、哼、DTMF、干擾、扭曲、一個微笑、脈衝、電子、上午無線電、EMF、無繩電話
資料來源：freesound ( https://freesound.org )