Double Curly Loop
Two curly loops, which represent a reel-to-reel tape recorder. Used as a symbol for voicemail on many phones.
A variation of this logo is used by Free Dial, a toll-free telephone number by NTT in Japan.
Double Curly Loop was approved as part of Unicode 6.0 in 2010 and added to Emoji 1.0 in 2015.