DNP3 is a poll/response protocol with high-level error checking built in. If all you are doing is polling, then the remote modem is simply set to udp auto answer. Since dnp3 supports report by exception, the remote modem must be in udp start up mode and have the master address/port set.
Step-by-step guide
Master Modem Configurations
Log into AceManager >> Serial
Configure the serial mode to "Variable Modbus"
Click on the Modbus column and add the RTU's to the Modbus Address List
RTU Modem Configuration (Remote modem)
Configure Startup Mode as "UDP"
Click on PAD on left side and enabled UDP Auto Answer
Configure the Destination port (This would be the Device Port number configured in the Master Gateway)
Configure the Destination Address (WAN IP address of the Master)
Notes:
For the MODBUS Address List
the range for index numbers is 0–255 (decimal) or 0x0–0xFF (hex). The Modbus address list accepts up to 100 entries.
Including the port number after the IP address is optional. If you include the port number, separate the port number and IP address by a colon (example: 10=123.123.123.123:11223 or 0xA=123.123.123.123:11223