4 ms·

Just yesterday there was a discussion about location services[1] If you connect your phone to a cell network, just by triangulation they got your home address..

Just yesterday there was a discussion about location services[1] If you connect your phone to a cell network, just by triangulation they got your home address...someone also mentioned that the phone will connect to nearest towers without a sim for 911 services... I guess is there hardware or software that can force the cellular modem to connect to a single tower of your choice? [1]https://news.ycombinator.com/item?id=35779816 https://news.ycombinator.com/item?id=35779816

theK 3y ago
Source selection logic most often is completely in firmware and as most antenna firmware are closely kept binary blobs that the soc comes preinstalled with. I would wager to say that, while possible to do, it is practically impossible for the average joe unless they own a Librem 5 which afaik is the only one with an open source antenna firmware.
- megous 3y ago
  Can you point us to the code for cell selection, then?
- rationalist 3y ago
  I haven't heard that about the Librem 5, just that they keep the modem seperate from the main processor and memory by keeping it as a USB device.
  - theK 3y ago
    Could be that I was wrong. I had seen this one: https://source.puri.sm/Librem5/bm818-tools https://source.puri.sm/Librem5/bm818-tools But it seems it doesn't include the firmware, just some utils.
kotaKat 3y ago
Every tower essentially allows an unauthenticated device to log on as an 'emergency' user to a special 'emergency' APN and grants an IMS connection to the emergency number (112/911/etc). See: https://www.sharetechnote.com/html/IMS_SIP_PSAP.html https://www.sharetechnote.com/html/IMS_SIP_PSAP.html ("Emergency Call without Normal Registration") My CBRS test networks all have their cells configured to explicitly deny an emergency bearer request for life-safety purposes. As soon as they see the deny they keep moving on to the commercial networks.
- kornhole 3y ago
  Is it possible to configure a device with usual SIM to deny or not connect to PNAS? Any info would be appreciated.

theK 3y ago

Source selection logic most often is completely in firmware and as most antenna firmware are closely kept binary blobs that the soc comes preinstalled with. I would wager to say that, while possible to do, it is practically impossible for the average joe unless they own a Librem 5 which afaik is the only one with an open source antenna firmware.

megous 3y ago
Can you point us to the code for cell selection, then?
rationalist 3y ago
I haven't heard that about the Librem 5, just that they keep the modem seperate from the main processor and memory by keeping it as a USB device.
- theK 3y ago
  Could be that I was wrong. I had seen this one: https://source.puri.sm/Librem5/bm818-tools https://source.puri.sm/Librem5/bm818-tools But it seems it doesn't include the firmware, just some utils.

kotaKat 3y ago

Every tower essentially allows an unauthenticated device to log on as an 'emergency' user to a special 'emergency' APN and grants an IMS connection to the emergency number (112/911/etc). See: https://www.sharetechnote.com/html/IMS_SIP_PSAP.html https://www.sharetechnote.com/html/IMS_SIP_PSAP.html ("Emergency Call without Normal Registration") My CBRS test networks all have their cells configured to explicitly deny an emergency bearer request for life-safety purposes. As soon as they see the deny they keep moving on to the commercial networks.

kornhole 3y ago
Is it possible to configure a device with usual SIM to deny or not connect to PNAS? Any info would be appreciated.