Thread:AmazingTLM/@comment-5683044-20170315205850

The early TSUG-OS systems had their own sound card. It was pretty distinct from other computers in El Kadsre at the time. Here are the card's modules:
 * The chip can only produce square waves, similar to some of Yamaha's "square wave" keyboards in the 1980s.
 * The chip has six voices that have sixteen waveforms to choose from. The pulse width ranges from 0.625 - 0.500.
 * The YM2149 is also included in this massive soundcard. They call it the Programmable Sound Generator, or PSG. It has three voices that can produce 50% square waves and noise. This chip was used in the PC-88/98, the MSX, and of course, as an expansion chip on the NES. 