User manual

Seriell RS-422/485 PCIe Board English

485-2W

485-4W

422

There are 2 sets of the jumpers to set the settings for port 1 (S1) and port 2 (S2)

respectively.

1. Mode Selection Jumper: JP4 for S1 and JP7 for S2

2. Termination Resistor Enable/Disable Jumper: JP8 for S1 and JP9 for S2

3. Echo or No Echo Selection Jumper: JP5 for S1 and JP6 for S2

4. TXD Control Selection Jumper: JP2 for S1 and JP3 for S2

485-2W = RS-485 Mode with 2-wire (Default)

485-4W = RS-485 Mode with 4-wire

422 = RS-422 Mode

1. Mode Setting:

This jumper is to set the transmission data will be echoed back or not. The Echo

mode is useful for the application program to detect if the RS485 bus has collision. If

the echoed data was not equal to the transmitted data, then the bus was in a colli-

sion. This setting only affects the RS485 2-wire mode. It doesn’t affect RS485 4-

wire, RS422, and RS232 modes.

2. Termination Resistor Enable/Disable:

This jumper enables/disables the 120 Ohm termination resistor between DATA+ and

DATA- of the RS485 transceiver:

OFF ON

OFF = Termination Resistor Disabled (Default)

ON = Termination Resistor Enabled

3. Echo or No Echo Settings:

OFF ON

OFF = No Echo Data (Default)

ON = Transmission data will be echoed

3.3 Jumper setting

JP4 for S1 Port

JP7 for S2 Port

JP8 for S1 Port

JP9 for S2 Port

JP5 for S1 Port

JP6 for S2 Port