The Pasco CI-6538 Rotary Motion Sensor is made to work with Pasco interfaces and can not be adapted to work with Vernier interfaces.

In contrast, there is a similar version marked CI-6625 can be used with a LabPro or LabQuest using the Rotary Motion Adapter (ROT-BTD).

Both versions use 2 digital lines, but the Pasco version that has 2 1/4 stereo jacks uses the 2 digital lines such that one is counting pulses, and the other is either high or low to indicate direction. The ULI version (CI-6625) uses one line to count in one direction and the other line to count in the other direction.