National Instruments AT E Series - Manual (Page 162)

Appendix C Common Questions
AT E Series User Manual C-10 ni.com
What are the power-on states of the PFI and DIO lines on the I/O
connector?
At system power-on and reset, both the PFI and DIO lines are set to high
impedance by the hardware. This means that the device circuitry is not
actively driving the output either high or low. However, these lines may
have pull-up or pull-down resistors connected to them as shown in
Tables 4-2 to 4-5. These resistors weakly pull the output to either a logic
high or logic low state. For example, DIO(0) is in the high impedance state
after power on, and Table 4-2,
I/O Signal Summary for the AT E Series ,
shows that there is a 50 k
Ω pull-up resistor. This pull-up resistor sets the
DIO(0) pin to a logic high when the output is in a high-impedance state.