Daniel Pfeffer wrote:
Thinking about it, the facility you describe would be less useful for mobile phones than it is for fixed phones. The mobile network must track the location of each phone, so each phone must have its own ID.
Well, mobile phones do have their own IDs! The mobile network will trace a mobile phone, whether you like it or not. You wouldn't have to use a mobile phone, though. Assume you live in an area (say a village) with WiFi coverage. Then you could sit down with your internet device - rather than a mobile phone - anywhere to connect you SIP client to the village SIP host. The host would fuse together the mobile phone termination with the SIP client on your internet device. If the called party is also a SIP subscriber, the connection would never touch any phone network at all. If a traditional phone number (POTS / mobile) is specified, the SIP host would establish a connection to that number and fuse it with the SIP connection to your internet device. In fact, you could go anywhere with your internet device, as long as your SIP client can connect to the village SIP host - that would be analogous to the mobile phone "I am here!" messages, not as a broadcast to all base stations but specifically aimed at the SIP host. You could of course use a SIP app on your smartphone. In that case, the smartphone could be tracked. Using a TLS encrypted link to the home SIP server, a tracker would know that you made some sort of connection home, but could not track it as a phone call and certainly not know who you were calling. With this home server being the subscriber for that common mobile phone number used by all, you wouldn't have your own smartphone, but would borrow one from the village phone office whenever you went on a trip where you couldn't expect to have WiFi coverage for your laptop or tablet. So a tracker of the mobile phone would know that someone from the village has been travelling here and there, but not that it was you. I do not expect people under 30 (or maybe it is 50 nowadays?) to be willing to give up the 342 apps installed on their smartphones, their immediate availability through the phone, the ability to X, take hundreds of photos and video clips for TikTok publishing. Well, maybe their laptop or tablet could provide some of this functionality. Or the smartphone you check out when going on a trip. I guess most young people would refuse to give up their private smartphone. So the in
