The EU2200i are only compatible with EU2000i or EU2000i Companion models within a specific serial number range:
EAAJ-2017305 through EAAJ-9999999
EACT-1000001 through EACT-9999999
Connecting an EU2200i with an EU2000i or EU2000i Companion that is not within the compatible serial range above may cause a low voltage output, which can damage tools and appliances powered by the generators. Units outside the compatible serial number range should only be paralleled with another EU2000i.
This is a quote from the Honda web site. Not what OP asked but important information if you have an older EU2000i as I have.