The following figure shows the factory-made wiring inside WSP152. You can use either RS-232 or RS-485 without any need of wiring changes on either side. The USB adapter will automatically adapt to the RS-232 or RS-485 selection in the WXT configuration.
The USB cable does not provide heating power for the device, only the operating power (max. 150 mA). If heating is required, lead the power cable from a separate supply through the HTG cable gland and connect the wires to host terminals 1 and 2 on the right hand side. You can leave the existing PNK and YEL wires there or disconnect them. If you disconnect them, cut and/or insulate them to prevent any short circuits.