Device-side Pin Assignments for IU-100, IU-110, and IU-120

This information is applicable to the following Synchrotech part numbers.

• USB-SIO-IU-100
• USB-SIO-IU-110
• USB-SIO-IU-120

These USB to serial devices feature DB9 connectors, frequently used in RS-232 applications. RS-422 and RS-485 tend to use different connectors, so speciality cables (e.g. DB9 to Mini Din 8) are often needed to accommodate certain serial peripherals. The above image and following table should be helpful in selecting or designing application specific cables to deploy with the IU-1** series USB to Serial device.

Pin	Transmission Signals
	RS-422	4-Wire RS-485	2-Wire RS-485
1	Tx-	Tx-	D-
2	Tx+	Tx+	D+
3	Rx+	Rx+
4	Rx-	Rx-
5	GND	GND	GND

See the user manuals for the individual devices for further information including: DIP Switch settings, and internal jumper settings.