3.5" Touch HMI device with RS-232/RS-485 port, USB port for firmware updates, RTC and Rubber Keypad. The TouchPAD VPD 3.5 inch H Series is a series of industrial touch HMI devices that features, 3.5" high resolution color touch screen LCD. With touchscreen capability, it is easy to deploy into all kinds of automation systems, and make them more intuitive and efficient. Either setup new system installations or complete system retrofits, VPD series..