There is a programming manual that might help too:
https://the-checkout-tech.com/manuals/cashregisters/Uniwell_DX-890_DX-895_DX-915_TX-870_TX-875_SX-700_SX-705_SX-800_SX-805_SX-7000_SX-7505_SX-8500_SX-8505_programming_manual.html
Registerman
December 2015