JLCooper sBOX8D - Manual (Page 18)

The outputs of the sBOX GPI ports are CMOS. The output signal
is referenced to pin 1 of the GPI Output Port. The GPI Outputs
deliver 0 or +5 volts and are rated to +/- 6mA.
Note: Because the outputs are CMOS, the output voltage MUST be limited to
voltage levels between 0 and 5 volts. This can occur if driving a circuit that is
powered by a voltage higher than 5 volts.
The example circuits below shows a GPI Output driving an LED.
This also applies to driving the LED of an optoisolator input.
74HC374
Detail of GPI Output
!
1
74HC374
GPI Output Example #1 with LED
2
5 Volts
!
1
74HC374
GPI Output Example #2 with LED
2
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