Also known as caller tunes in some countries, such as India, ringback music is a service offered by mobile network operators to permit subscribers to select music or even install personalized recorded sounds for audible ringing.
Early versions of personalized ringback tone systems were invented by Kang-seok Kim (Korean patent 10-1999-0005344), Mark Gregorek et al. (U.S. 5,321,740) and Neil Sleevi (U.S. patent 4,811,382).
The first functional ringing tone replacement system was invented by Karl Seelig et al. (U.S. patents 7,006,608 and 7,227,929). In 2001 Seelig’s prototype was described in the Orange County Register and the Economist Magazine.