Moxa Technologies UPORT 1110 - RS-485 Port Configuration

UPort 1100 Series Introduction
1-6
Adjustable Pull High/low, Terminator Resistors for the
RS-485 Port
In some critical environments, you may need to add termination resistors to prevent the reflection of serial
signals. When using termination resistors, it is important to set the pull high/low resistors correctly so that the
electrical signal is not corrupted. The UPort uses DIP switches to set the pull high/low resistor values for each
serial port.
To set the pull high/low resistors to 150 KΩ, make sure both of the assigned DIP switches are in the OFF
position.
To set the pull high/low resistors to 1 KΩ, make sure both of the assigned DIP switches are in the ON
position. This is the default setting.
SW
1 2 3
Pull High Pull Low Terminator
ON 1KΩ 1KΩ 120 Ω
OFF
150 KΩ
150 KΩ
Disable