Thanks for your help SeanB,
Scale output specs are attached, it is the Analog version. My DRO does its own subdivision of the sine wave I can pick the divisor from 2 to 100 to get the resolution I want from the scale. (raw scale signal period is a separate entry)
I don't really understand what a differential current signal is, differential voltage I understand. Maybe both the plus and minus signal individually go to the ground of the 5V system through their own 1k resistor and then you take a differential voltage measurement between the two resistors? That would be the current differential wouldn't it?
I could crack open the DRO and try to identify how it is terminated as it comes in from the connector but I thought I would try to get some help first.
Thanks again, robrenz