National Instruments NI 783xR - page 36

Chapter 2 Hardware Overview ofthe NI 783xR
© National Instruments Corporation 2-17 NI 783xR User Manual
Figure 2-10. Example Digital I/O Connections
Figure 2-10 shows DIO<0..3> configured for digital input and DIO<4..7>
configured for digital output. Digital input applications include receiving
TTL, LVTTL, CMOS, or LVCMOS signals and sensing external device
states, such as the state of the switch shown in Figure 2-10. Digital output
applications include sending TTL or LVCMOS signals and driving external
devices, such as the LED shown in Figure2-10.
The NI78 3xR SH68-C68-S shielded cable contains 34 twisted pairs of
conductors. To maximize the digital I/O available on the NI783xR, some
of the DIO lines are twisted with power or ground and some DIO lines are
twisted with other DIO lines. To obtain maximum signal integrity, place
edge-sensitive or high-frequency digital signals on the DIO lines that are
paired with power or ground. Because the DIO lines that are twisted with
other DIO lines can couple noise onto each other, use these lines for static
*3.3 V CMOS
†Use a pull-up resistor when driving 5 V CMOS devices.
LED
TTL, LVTTL, CMOS, or LVCMOS Signal
+5 V
Switch
I/O Connector
DGND
NI 783
x R
DIO<0..3>
DIO<4..7>
+5 V
5 V CMOS†
TTL or
LVCMOS*
Compatible
Devices
DGND