Instruction Manual
3
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JP1: RS-422/485 Mode Selector
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 ATTATM 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:
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.
