Yeah, there are a number of customers that don't ship ECOMs as part of their systems, but own a single separate H0, H2 and/or H4 ECOM/100s for "development" and "trouble shooting". Basically, it's part of their "cable"

Remember though, you gotta have an open slot in the local base to plug in this "cable" (which could very well be an issue w/05 PLC)