NI 9403 Operating Instructions and Specifications 8 ni.com
Refer to Figure2 for an illustration of several types of digital devices connected to the NI 9403.

Figure 2. Connecting Digital Devices to the NI 9403

TTL Signal
+5 V
+5 V
LED
DIO0 as Input
DIO1 as Input
COM
DIO2 as Output
NI 9403
Dev 3
Dev 2
Dev 1