Macintosh: Serial Port HSKo Voltages (1/95)


I am trying to determine what voltages should be on the Macintosh serial connector.

As you look at the Macintosh serial connector, it is numbered like this:

8 7 6
5 4 3
2 1

Pin Signal Name Voltage Specification
---------------------------------------------------------
1 HSKo Vouth 3.6V Voutl -3.6V Rl= 450ohms
2 HSKi Vinh 0.2V Vinl -0.2V Ri= 12Kohms
3 TxD- Vouth 3.6V Voutl -3.6V Rl= 450ohms
4 GND Signal Ground
5 RxD- Vinh 0.2V Vinl -0.2V Ri= 12Kohms
6 TxD+ Vouth 3.6V Voutl -3.6V Rl= 450ohms
7 Gpi Vinh 0.2V Vinl -0.2V Ri= 12Kohms
8 RxD+ Vinh 0.2V Vinl -0.2V Ri= 12Kohms

Absolute values of specified voltages are minimums.
Ri is a minimum, Rl is a maximum.


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Published Date: Feb 19, 2012