Master Reset to an EGX100, EGX300, EGX200 or EGX400 gateways are needed to be done remotely through register write.
A master reset to an Ethernet Gateway (EGX) will reset all settings to the manufactures default settings including the IP address.
For the EGX100 and EGX300, the default IP address is 169.254.0.10. For the EGX200/400 it is 10.10.10.10.
Modbus Tester software or some other Modbus TCP/IP program (like Modscan) can be used to send the master reset register write.
For the EGX100 and EGX300 use address 254 and write decimal 9030 to register 2800.
For the EGX200 and EGX400 use address 254 and write decimal 17476 to register 8000.
Once you have sent this register command to the EGX you will have to cycle power to reboot the processor.