Definition of RS422 and RS485 Modes
To avoid any misunderstanding of what the RS422 and RS485 modes are, let's clarify that the term "RS422 mode" refers to a full-duplex differential signaling interface with at least RX and TX signals, and possibly with CTS and RTS signals. Each signal is carried by a pair of "+" and "–" lines.
The term "RS485 mode" refers to a half-duplex differential signaling interface with RX and TX lines, where each signal is also carried by a pair of "+" and "–" lines. The RTS line of the serial port is used (within the serial controller) to control the direction, so TX and RX lines can be combined (externally) to form a two-wire bus that carries data in both directions. On a physical signal level (voltages, etc.), there is no difference between the RS422 and RS485 modes — they are implemented in the same way.
The RS422 and RS485 modes typically require termination circuits. No such circuits are provided within the DS1102 and WS1102. A simple 120Ω resistor (added externally) is sufficient to terminate one "+/–" pair properly.