StarTech.com PCI2S485 Instruction Manual page 6

H H a a r r d d w w a a r r e e G G u u i i d d e e - - c c o o n n t t ' ' d d
JP1: RS-422/485 Mode Selector
Jumper Name Jumper Positions Mode and Termination Resistor Setting
485/422
RTS/AUTO
ECHO/NO_ECHO
LOOP/NO_LOOP
Please note: When set to "422" mode, the other settings (AUTO, ECHO and
LOOP settings) will have no effect.
Echo mode is used to detect data collisions. If the echoed data
was not equal to the transmitted data, then data collisions are
occurring.
If you want to set the RS-485 transceiver to "AUTO" mode, you
must duplicate this setting from the Windows Device Manager. You
only need to perform this step once, as this information will be
retained by Windows.
Please note that S1 and S2 have individual settings, and need to
be configured separately.
Instruction Manual
485
(Default)
422
RS-485 Transmitter Buffer Enable is
RTS
Controlled by RTS (active high)
AUTO RS-485 Transmitter Buffer is controlled
(Default) automatically by ATTATM hardware circuit
ECHO Transmitting data will be echoed back
NO_ECHO
(Default)
LOOP RTS will be connected to CTS
NO_LOOP
RTS and CTS operate normally
(Default)
3
2-wire RS-485 mode
4-wire RS-422 mode
No echo data