This PCB is a clone of the CEM 3374 VCO IC used in analog synthesizers from the early 1980s such as:

* Fender Chroma Polaris
* Oberheim Matrix 12
* Oberheim Xpander
* Akai VX600

It is designed to operate with 12V for Vcc and -5V or -6V for Vee, which is what all of the synthesizers listed above use for supply voltages. The circuit contains two oscillator channels with triangle and sawtooth wave outputs. Triangle wave outputs have an amplitude of 1/3 Vcc, and sawtooth wave outputs have an amplitude of 2/3 Vcc. It also has channel A sync and a temperature compensated reference voltage for the external DAC.