Heidenhain DRO and non genuine replacement scales

I acquired a Heidenhain DRO box only from ebay here in Australia (The
big dry down under!).
Appears to be NOS (New Old Stock) model VRZ710C, 2 axis. I now want
scales for it so I can play. Heidenhain scales are a little bit
aoutside my current budget.
Does anyone know if non genuiune scales will work with this
Heidenhain DRO. Dont care it I have to modify cable pinouts etc for
other brands.
If I knew the different manufacturers protocols, might even be able
to design a logic hardware interface for different manufacturers etc
to interface, for example, brand X DRO's with brand Y or Z scales,
and so on.
Regards
Shane M Dwyer