Digi WAN 3G User Manual page 146

Industrial Automation/Modbus Bridge
Industrial Automation is supported in these Digi devices: Digi Connect WAN IA,
Digi Connect WAN 3G IA.
Currently, from the web interface, it is only possible to select a different port profile than
Industrial Automation, or change the serial port settings, such as baud rate and parity. If changes
are needed from the settings established by the Industrial Automation port profile, use the set ia
command from the command-line interface.
Known limitations
Digi RealPort can be used only if the Modbus Bridge function is disabled. RealPort with

Modbus/RTU or ASCII cannot be used to access the Modbus Bridge function.
 The outgoing slave idle time used for remote Modbus IP-based slaves does not always
close idle sockets predictably.
While the Modbus bridge is active, do not attempt to "Port Forward" TCP 502 or UDP

502 to local Modbus/TCP servers while the Modbus Bridge is active. This causes
neither function to work. Disable the Modbus Bridge if traditional Router/NAT function
for Modbus/TCP port 502 is desired.
Disabling and enabling the Modbus Bridge
To disable the Modbus Bridge, select a different port profile than Industrial Automation. To enable
it, reselect the Industrial Automation port profile. Any specialized settings that had been set
through "set ia" commands are lost by disabling the Modbus bridge. They must be reconfigured
when you reselect the Industrial Automation profile.
More information on Industrial Automation/Modbus
For more information on Industrial Automation, see the "set ia" command description in the Digi
Connect Family Command Reference, and the application note Remote Cellular TCP/IP Access to
Modbus Ethernet and Serial Devices, part number 90000773, available on the digi.com Support
page at http://www.digi.com/support.
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