Macurco Modbus RS-485 User Instructions page 10

Set the switches to the desired value and then set switch 1 to ON and then OFF and the new settings will be saved in EERPOM.
The result of saving operation is displayed on LED: Alternating RED/OFF every 200 milliseconds indicates that saving new settings
failed and Alternating GREEN/OFF every 200 milliseconds indicates that saving new settings passed. Once the new settings have
passed, set the address for the device using the Address switches.
Line Termination - End of Line Resistor
The MRS-485 adapter is wired in the standard 2W-Modbus circuits definition with selectable built-in terminating resistors at the ends
of the RS-485 bus. The MRS-485 provides integral termination for end of line resistors (EOL). The MRS-485 termination uses 4 pin
connector with jumper to select termination: The user selects no termination or one of the two Modbus line termination options. The
MRS485 has two line termination options provided onboard that should cover most situations.
Place the EOL jumper on one of the following positions:
1 = 100 ohm
2 = 120 ohm
N = No termination (default)
If Line Termination requirements are different than those provided then the line termination will need to be provided by the installer.
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