Most if not all of these calipers provide the pins for a serial readout.
On the cheaper ones however, there is no access to the pins - makes for a cheaper one piece plastic moundling I guess.
If you're willing to get stuck into the caliper housing with a Dremel, you can get at the PCB to connect them to an external decoder.
I have a couple of these that allow connection of up to 3 scales/calipers for use as a digital readout on a mill or lathe.
