Chinese DRO/Caliper 4 pin interface

The cheap Chinese caliper and DRO's have a 4 wire interface. Has
anyone interfaced to one of these? Any info would be appreciated. I'm
thinking of using one for probing... Use the mill to step to a
position, gravity drop probe attached to DRO, read serial data, pick
up probe, next. I'd like to avoid using Z-axis as a simple pick up
and drop would be much faster than feeding.

I know, I can figure it out with the scope but it would be so much
easier if someone already knows.

Roger