"The trick is (and we never asked or found out) is that most of the time the remote digi-box is actually a carousel of SIM cards with unlimited local calls. The

"The trick is (and we never asked or found out) is that most of the time the remote digi-box is actually a carousel of SIM cards with unlimited local calls. The carousel is used to automatically distribute the calls over the SIMs to impede fraud detection by the mobile carrier." I have seen this in action ... I was working late at night in our (rsync.net) Zurich datacenter and there was a man who had a very tall stack of SIM cards that he was punching out and inserting into these long PCI cards ... I couldn't not ask him what he was doing. He was a little cagey about it, but I got the general idea (thanks, Swiss folks, for all speaking english!). The thing I don't understand is, to whatever degree running all those cards through a single SIM is a fraud alert, then I would think running all of those calls through a single tower would be an even bigger fraud alert. And yet, that doesn't seem to be a problem.