HwB: Mac to C64 Nullmodem Cable

Mac to C64 Nullmodem Cable

The RS-232 standard on the C64 is a little bit strange. It uses inverted TTL level for the signals. The RS-422 ports on the Macintosh has both an inverted and non-inverted input. By using the inverted instead of non-inverted the inverted C64 level is back to normal.

(At the Computer)
(To the C64).

8 PIN MINI-DIN MALE to the Macintosh.
DZM 12 DREH to the C64 UserPort.

	Mac	C64
GND+RXD-	4+5	1+12+A+N	GND
RXD+	8	M	TXD (PA2)
TXD+	6	B+C	RXD (FLAG2+PB0)
		D+E	RTS+DTR (PB1+PB2)

Contributor:  Joakim Цgren, Pierre Olivier

Source: Usenet posting in comp.sys.cbm, A very simple C64 to Macintosh serial cable by ">Chris Baird

Please send any comments to Joakim Цgren.