A call return service which automatically dials the number from which the last incoming call was made, activated by pressing the ‘star’ (*), 6, and 9 buttons.
1990s; earliest use found in Usenet (newsgroups). Either from star + sixty + nine, or from star + six + nine, with reference to the sequence dialled on a touch-tone telephone to make use of the service.
star 69/ˌstɑː sɪkstɪˈnʌɪn/ /ˌstɑː sɪksˈnʌɪn/
with object To use the star 69 telephone service to call (a person or a person's number).
1990s; earliest use found in Usenet (newsgroups). From star 69.