AAxeon MSC-102B Installation Manual - page 6
RS-422/485 Multiport Serial PCI Card
4
3.1.2 JP1: RS-422/485 Mode Selector
Mode Settings for both S1 and S2 (JP1):
Jumper Name
Jumper Positions
Mode and Termination Resistor
Setting
485/422
485
(Default)
2-wire RS-485 mode
422
4-wire RS-422 mode
RTS/AUTO
RTS
RS-485 Transmitter Buffer Enable is
Controlled by RTS (active high)
AUTO
(Default)
RS-485 Transmitter Buffer is
controlled automatically by ATTA
TM
hardware circuit
ECHO/NO_ECHO
ECHO
Transmitting data will be echoed
back
NO_ECHO
(Default)
No echo data
LOOP/NO_LOOP
LOOP
RTS will be connected to CTS
NO_LOOP
(Default)
RTS and CTS operate normally
Please note that if the mode were set at “422” mode, the
other settings (AUTO, ECHO and LOOP settings) will take no
effect.
The Echo mode is useful for the application program to
detect if the RS-485 bus were in a collision. If the echoed
data was not equal to the transmitted data, then the bus
was in a collision.
If you want to set the RS-485 transceiver to “AUTO” mode,
you have to go to Windows Device Manager to turn on
this option as well. You only need to do it once and the
Windows will keep the settings afterward. Please note that
422
AUTO
NO_ECHO
NO_LOOP
485
RTS
ECHO
LOOP