Hardware Setting & Mode Configuration

Inside the unit, there is one 4-pin DIP switch which is set to select the mode ofoperation. You need to push down the upper case, and slide it open by following the direction of the arrow in the illustration below. You can set the switch settings to RS-232 mode, RS-422 mode, or RS-485 mode, as per the requirements of your application. After setting of switches, you then proceed to insert the driver CD and start driver installation.

 

The RS-232 & RS-422 & RS-485 Mode Block Configuration Settings are listed as follows.

Push down the upper case and slide it to open

 

RS-232 & RS-422 & RS-485 Mode Block Configuration

 

SW (External DIP Switch) for Mode Setting
  Operation  Mode  S1  S2  S3  S4
RS-232 Standard RS-232 Mode
OFF
ON ON ON
RS-422
4 wire with Handshaking ON ON ON ON
RS-485 Full Duplex (4 wire) ON
OFF
ON ON
Half Duplex (2 wire) with Echo ON
OFF

OFF
ON
Half Duplex (2 wire) - without Echo ON
OFF

OFF

OFF

 

4-pin DIP switch for operating mode selection

 

Inside the unit, there is one 3 x 7 (21 pin) header blocks which are jumpered to enable Tx, Rx, CTS 120 Ohm termination resistors and Tx, Rx 750 Ohm BIASing resistor.  

You will need to push down the upper case, and slide it open than set the jumper setting for RS-422 mode or RS-485 mode as per the requirements of your application.

 

Settings are listed as follows:

Jumper Function
1-2      enable
2-3      disable
Tx Termination of 120 Ohm. This jumper should always be populated for RS-485 mode.
4-5      enable
5-6      disable
Pull-up Tx+ to VCC by 750 Ohm Bias resistor. This jumper should be populated for pull-up Tx+.
7-8      enable
8-9      disable
Pull-down Tx- to GND by 750 Ohm Bias resistor. This jumper should be populated for pull-down Tx- .
10-11  enable
11-12  disable
Rx Termination of 120 Ohm. This jumper should always be populated for RS-422 mode.
13-14  enable
14-15  disable
Pull-up Rx+ to VCC by 750 Ohm Bias resistor. This jumper should be populated for pull-up Rx+.
16-17  enable
17-18  disable
Pull-down Rx- to GND by 750 Ohm Bias resistor. This jumper should be populated for pull-down Rx-.
19-20  enable
20-21  disable
CTS Termination of 120 Ohm. This jumper should always be populated for RS-422 mode.

 

Note: Sometimes, when operating in RS-422 or RS-485, it is necessary to configure termination and biasing of the data transmission lines. Generally this must be done in the cabling, since this depends on the installation of connections. Before applying the option, check your cable specification for proper impedance matching.

 

Biasing of data lines must only occur at a single point anywhere in the cabling. USB-COMi + provides biasing for ease of installation. Please be sure to disable this inside the unit, if your cabling already provides biasing.

 

Termination must not be installed in the middle of the cable. It is only permitted at both ends. Since a computer controlled serial port is almost always at one end of the cable, termination is disabled by default.

7x3 header block for enable the termination and biasing resistors

 

RS-232/422/485 Pin-outs & Signal Wiring

RS-232 Signal Pin-outs of DB-9 Male

 

Pin 1 DCD
Pin 2 RxD
Pin 3 TxD
Pin 4 DTR
Pin 5 GND
Pin 6 DSR
Pin 7 RTS
Pin 8 CTS
Pin 9 RI

 

RS-422 Signal Pin-outs of DB-9 Male

 

Pin 1 Tx- (A)
Pin 2 Tx+(B)
Pin 3 Rx+(B)
Pin 4 Rx- (A)
Pin 5 GND
Pin 6 RTS- (A)
Pin 7 RTS+(B)
Pin 8 CTS+(B)
Pin 9 CTS- (A)

 

RS-422 Signal Wiring

 

Point-to-Point 4 Wire Full Duplex
 

USB-COMi +                               RS-422 Device

RS-422 with Handshaking

 

USB-COMi +                       RS-422 Device

 

RS-485 4-Wire (Full duplex) Signal Pin-outs of DB-9 Male

 

Pin 1 Tx- (A)
Pin 2 Tx+(B)
Pin 3 Rx+(B)
Pin 4 Rx-(A)
Pin 5 GND

 

RS-485 2-Wire (Half duplex) Signal Pin-outs of DB-9 Male

 

Pin 1 Data- (A)
Pin 2 Data+(B)
Pin 5 GND  

 

RS-485 Signal Wiring

 

Point-to-Point 4 Wire Full Duplex
 

USB-COMi +                          RS-485 Device

 

Multidrop RS-485 2-Wire Half-duplex

 

            USB-COMi +                               RS-485 Device