[Digital Output Problem] PCI-DIO-96

I am using a NI I/0 card (PCI-DIO-96) with DAQmx libraries under Linux.

I compiled and run the example WriteDigChan.c.

After i run this example, i used a multimeter to measure the voltage at each line and check if the card is working properly.

The problem is that when a line is set to logic low (0) the voltage i measure is ~4,916 Volts and when a line is set logic high (1) the voltage i measure is 0 Volts.

Shouldn't be viseversa? Or am I missing something?