Solution
The NI-6584 is a device intended for interfacing RS-422 and RS-485 devices. As such it adheres to the output voltage ranges of the standard. The NI-6584 will output 3V with a typical output drive in the range of 25mA-35mA. Note that this is not listed in the
NI-6584 Specifications Document and is therefore not a warranted specification.
The voltage level is not adjustable in software (i.e. the NI-6584 can not be set to output 5V logic).