Software platforms were custom written to handle money collection and transfer, connecting caller and sex worker though neither could see anything but the platform's phone number, and metering the connection.
Performers would come to a studio where they received a cubicle, coaching, and cash incentives to keep callers on the line longer.
Once means of transmitting payment were developed, phone sex turned into primarily a commercial activity, with customers (overwhelmingly male) and sellers (overwhelmingly female).
Due to the potential for emotional intimacy between those who have engaged in phone sex, it is a matter of some debate whether phone sex is to be considered infidelity when involving a person outside of a committed personal relationship.
Nevertheless, phone sex should not be confused with prostitution wherein money is exchanged for real life sexual services or physical interaction.
The editor of High Society magazine, Gloria Leonard, is credited with being one of the first people to use "976 numbers", then "900 numbers" for promotional purposes and soon as a revenue stream in the adult industry.
By the end of the 1980s, nearly all of the major local phone companies in the United States, plus the major long distance carriers, were actively involved in the adult chat line business.