Additional Information
PXIe-6535 is compatible because 5V TTL detects high when the signal over 2.7V is received. The minimum voltage 3.2 V from PXIe-6535 is high enough to be detected as high in 5V TTL system. Therefore, you can use PXIe-6535 in 5V TTL system with 3.3V digital output.
Here is the 5V TTL system of input and output.