The Commodore is a home computer from the 1980s. It has a number of interfaces which can be used to interface with the outside world which include a serial UART, 8-bit parallel port, cassette port and CBM IEC serial bus.

 1    2    3    4    5    6    7    8    9    10   11   12
GND  5V   RES  P2   P3   P4   P5   RxC  ATN  9VAC 9VAC GND

GND  P0   RxD  RTS  DTR  P7   DCD  P6   P1   DSR  TxD  GND
 A    B    C    D    E    F    H    J    K    L    M    N