There was no audio on the original PETs
I am pretty certain that there was no audio at all on the original PETs. My school replaced our PDP8f with a handful of PETs . The magazines of the time had articles about connecting a loudspeaker through a simple transistor amplifier to the 6522VIA serial data line to make sound. This line was available on the user port, and could loaded with data and clocked out by setting internal 6522 registers. It was never used for serial communications though.
Biting the hand that feeds IT
