Eterm xplus amdus Galileo What's the difference between these systems?

eterm is not a system, but a software. The name of the system is travelsky, and it is called GDS (Global Distribution System), which is used to book and sell air tickets and hotels. The difference is only that it uses regions and companies. Because China is monopolized by travelsky, all of them use TravelSky, and other countries and regions are using different distribution systems!