E. Barnes, Professional Gamer, Professional Gamer, Washington
Answered Jun 04, 2019
Yes. There are indeed three ethernet devices without backwards compatibility. The first released XBox 1 was not compatible. The CFPx family has no backward compatibility, for one. 5G is also not backward compatible so those devices are exclusions when it comes to being backwards compatible. PlayStation 4 is not backwards compatible either.
There are actually more than 3 that are not backwards compatible but those are at least three of them. The term backward compatible has to do with the property of a system, or a particular product, or a specific technology that allows for it to interoperability with a legacy system which is older or with a special input designed to allow such a system to work backwards. These modifying devices are common for computing and sometimes for telecommunications too.