It was created in 1990 by Texas Instruments via a DARPA grant, and released in 1992 by NIST.
The corpus contains 2,400 telephone conversations among 543 US speakers (302 male, 241 female).
[1][2][3] Participants did not know each other, and conversations were held on topics from a predetermined list.
[4] Switchboard-2 Phase II was collected in 1999 and includes "4,472 five-minute telephone conversations involving 679 participants".
Oh wow my dad used to work at UTD also B: Yeah so I [vocalized-noise].