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This connector is not present on Macintosh 128K, 512K, and 512K enhanced computers. To connect DE-9 cables to the Mini DIN-8 port, use adapter cable 590-0341 (beige) or 590-0553/699-0430 (smoke).. a. On serial port A (modem), if the VIA1 SYNC signal is high, this input will be routed to the receive/transmit clock input of the SCC. This clock input supports high-speed synchronous devices. Pin 7 is not connected on the Macintosh Plus, LC, or IIsi.
####Pin Signal Description1 HSKo Handshake out2 HSKi Handshake in/external clock3 TxD- Transmit data -4 GND Signal ground5 RxD- Receive data -6 TxD+ Transmit data +7 GPI/ NC General-purpose input orno connection8 RxD+ Receive data +

0,0	0,1
1,0	1,1