Notes

One source says the presidential BlackBerry can only connect to a secure base station, which can be used to hide the IMEI-number of the device and thus prevent tracking it. This would mean the White House Communications Agency has to carry such a secure base station wherever the president goes.

There must be also a secure base station inside the presidential limousine, as we can see in the picture above. First because using a foreign cell phone network would be a big security risk, but also because the limousine is most likely constructed like a Faraday cage, and therefore a BlackBerry could only be used if there’s a base station in the car itself (and probably also in Air Force One). The secure base station is probably connected to a secure satellite link with Washington. How Obama’s BlackBerry got secured