Uniwell do not give this information out as it can be used for fraud. You need to get the dealer programming manual. There is one at C-tech. Try this:
https://the-checkout-tech.com/manuals/cashregisters/Uniwell_PX-5700_PX-5750_PX-6600_PX-6700_PX_6750_Type_05_Programming_manual.html
Registerman, January 2015