The serial bus is a serial form of the IEEE-488 bus that was used by the PET. It was compatible with all 8 bit Commodore computer peripherals that came after the VIC-20. The connector is a 6 pin DIN socket located on the back of the VIC-20, in between the video output jack and the cassette tape port.
The most common peripherals that made use of this port were peripherals such as disk drives and printers. Up to four disk drives and one printer could be daisy chained to a Commodore VIC-20.
Printers & Plotters
|1||VIA #2 CB1||SRQ in (unused)|
|3||VIA #1 PA7||ATN out|
|4||VIA #2 CA2||CLK|
|5||VIA #2 CB2||DATA|