Product Highlights Industrial Serial Port the DE9 RS-485 connector plugs right into Computrols products. Membrane Keypad Light and rugged with textile feedback. No Battery Required The HHT takes its power directly from the controller - no plugs, no chargers. Backlit LCD Helpful for dark environments. No Updates Needed Because the HHT is driven by the controller, all the controller's features are available and no one-board software is required. Lifetime Warranty Our quality speaks for itself.