I assume you're using ControlLogix.
In this case "generic Ethernet module" is a misnomer. It should say "Generic EtherNet/IP Adapter Device".
Such an entry in the I/O tree of the ControlLogix/CompactLogix project has to be an EtherNet/IP Class 1 Adapter. It's not literally "some generic device on Ethernet".
You probably need some kind of ASCII-to-EtherNet/IP gateway, or you need to write an application for the generic sockets feature.
What exact device is it ?