NEC μPD7720

In the late 1970s, telephone engineers were attempting to create technology with sufficient performance to enable digital touch-tone dialing.

[1] Existing digital signal processing solutions required over a hundred chips and consumed significant amounts of power.

[2] Intel responded to this potential market by introducing the Intel 2920,[3] an integrated processor that, while it had both digital-to-analog and analog-to-digital converters, lacked additional features (such as a hardware multiplier) that would be found in later processors.

[1] Announcements for the first "real" DSPs, the NEC μPD7720 and the Bell Labs DSP-1 chip, occurred the following year at the 1980 IEEE International Solid-State Circuits conference.

[6] Beyond their initial use in telephony, these processors found applications in disk drive and graphics controllers, speech synthesis and modems.