Adder Technology SMARTVIEW PRO SV12PRO - Manual (Page 39)

SmartView Installation and Use Page 38
RS232 serial mice - these require a special converter to connect the RS232 lines
present on the SmartView mouse ports to the RS232 port on a PC.
Cables should be no longer than 30 metres.
A3. Expansion port pin assignments
The 15 way D connector located on the back of the SmartView provides connections
for the remote control module and allows an external RS232 device to control the
SmartView. See section 3.5 for more details.
Pin 9 = GND
Pin 11 = RXD
Other pins to be left unconnected