Just got back from a couple weeks in Germany and I noticed something strange.

I have my phone set to automatic network selection. When I switched to the Riiing SIM it would invariably choose vodophone.de first. However dialing any US number (such as my CBW trigger) would generate an error -- the phone would ring and I would get a "could not connect" message. This would be the first callback that Riiing does, not the callback from CBW.

Switched the phone to manual network selection, chose T-Mobile and everything worked fine. So maybe vodophone and riiing are not getting along :)

I didn't think to try any of the Riiing numbers (balance, voice mail, etc) while on vodophone.

Just F/Y/I

Vodafone and riiing/UM don't seem to jive too well together. Problems were also reported back in September of last year by Matha531.