Wiring encoder to 7330 board.

So, I'm building motion system based on NI-7330 and stepper motors and came up with a problem concerning wiring encoders. I've got an WEDL5541-A06 Encoder with line driver output signals so it's 8 wires otuput, but Motion Board has only 3 inputs (A, B and ~I - inverted Index) so I connected them like there are only 5 outputs from encoder ( using 0V, Vcc, A, B and ~I). Did all connections as it is shown in encoder manual (PDF - WEDS encoder connector config. ) and wired A,B and ~I to the NI-7330.

I checked the encoders using MAX and it seems like they are counting about 1/10 of actual steps (when making more than few full revolutions) and not counting steps at all when making single steps.

Do You have any idea why is it like this?
Are there any mistakes in wiring or should I make some configuration concerning encoders in MAX? (I set filter frequency to 100kHz and 500 pulses per revolution as in encoder manual.)