The UART interface can have different implementations at the physical layer. For example, TTL signals have a voltage of 0 to +3.3 or up to +5 volts. RS-232 has a voltage of -10 to +10 volts. RS-485 does require two wires for each signal. Therefore, if, for example, Arduino has a TTL interface, and the display is RS-232, then they will not be able to communicate directly with each other, without a TTL – RS-232 converter.
Industrial series stone displays can have any of these three options, this is indicated in the exact model name in one of the last digits.