This month is the 25th anniversary of the Sony Walkman.
A midnight-blue-and-silver brick with astonishing sound debuted in July 1979. Called the Soundabout, Sony's TPS-L2 cassette player was an investment at $199.95.
It didn't record or come with a speaker. But it was sociable: Two could listen at once through a pair of headphone jacks, and an orange button called the Hotline let you talk over the music.
How did it let you talk over the music? Was there a microphone to put your voice through the headphones, or did it just lower the volume? Did anyone have one of these?