Please have a look at this video for your reference. Private call to 9990 is Brandmeister network echo test. The Openspot 2 own echo test ID originally set to private/group calls 9999. You can check it on Openspot2 web interface settings page DMR settings section. If you want to call Deutschland or Switzerland it should be group calls 262 or 228.
https://www.youtube.com/watch?v=5-9SGWXLyjQ