When you install the EL2, you will see four options (EL-2.0, EL-2.1, EL-2.2 and EL-2 485).
To install the EL2 properly, make sure to use the following guidelines in selecting your specific model:

The EL-2.0 is the 232 version of the EtherLite 2.
The EL-2.1 is no longer valid.
The EL-2.2 is the 422 version of the EtherLite 2.
The EL-2 485 is the 485 version of the EtherLite 2.