Of course it is always tricky to interconnect two systems that have a different and potentially conflicting numbering plan. I actually like the numbering plan they use here. You number is not tied to the PBX you have registered on, but it roams with you wherever you connect. So when the local situation changes (someone stops providing the service or some more nearby PBX appears where you have better connectivity or better services) you can just port your existing number without problem. And no directory is required, I can just dial numbers on the keypad knowing only the callsign. For you it would be 62206142 It would have been even better when they had thought of having some unique prefix that makes it recognizable as a HAM number and not a POTS phone number, and that avoids collisions with other numbering plans. Rob