ADLINK PCI-8154 - Manual (Page 77)

Operation Theory 67
Single Pulse Output Mode (OUT/DIR Mode)
In this mode, the OUT pin is for outputting command pulse chain.
The numbers of OUT pulse represent distance in pulse. The fre-
quency of the OUT pulse represents speed in pulse per second.
The DIR signal represents command direction of positive (+) or
negative (-). The diagrams below show the output waveform. It is
possible to set the polarity of the pulse chain.