4 ms·

You can probably just enable Airplane Mode on your phone and expect that to work fine.

Zigurd 2y ago
It's been since 3G that I delved into baseband specs in any depth, but I would not trust a powered up phone not to be commanded to connect to a network.
- adamomada 2y ago
  Couldn’t this easily be proven by monitoring transmission power from the device? There are all sorts of people who go on vacation and use the switch to avoid roaming charges. It would be plainly obvious to those people that their supposedly offline phone went online when they look at their bill. Or is there some secret apn bypass?
  - Zigurd 2y ago
    Depending on how careful you are and what equipment you've got on hand, you might be able to detect that going on, but I think "easily" is a stretch. If there is a secret involved in this it would be undocumented commands sent by the network to phones that then interpret them as commands to connect to the network, plus baseband processors the periodically look for such commands. They don't radiate, so very little power is used, but they should be entirely dormant.
  - ranger_danger 2y ago
    I ask this all the time but have yet to find anyone that has actually measured it. According to Snowden, basebands are still powered and operational even when the main application OS (android/ios/etc.) are shut down. And a non-removable battery sure doesn't help that. Plus, he also says that the baseband often has its own separate connections to the GPS, microphone and camera and can operate them without the application OS involved. If the baseband is still powered, I can only assume it is simply sending (or responding to) periodic commands that do not require network authorization, which could possibly still let the network know where you are even without involving any roaming charges.
- richjdsmith 2y ago
  Or even a phone that is "off". Newer iphones (11+) can be found through the FindMy network, even when the device is off. https://9to5mac.com/2021/07/21/ios-15-here-are-the-devices-that-support-find-my-when-turned-off/ https://9to5mac.com/2021/07/21/ios-15-here-are-the-devices-t...
  - deleted 2y ago
    [deleted]
kevin_thibedeau 2y ago
Modern cars have their own internal GPS and cellular links. Even if they don't have mapping, it's probably still there, always on for tracking and compass bearing.
- ssl-3 2y ago
  GPS is even used for automatic HVAC controls in some vehicles. A light sensor is used determine the amount of sunlight streaming and heating the interior. GPS data is used to help calculate the angle of the sun, and determine which areas are likely to be heated the most, and thus needs more cooling. A compass can be used to make it work even when the car is stationary (when GPS heading is unavailable). A singular interior temperature sensor can be used for feedback, injecting some truth to balance things out. It may seem far fetched or even fanciful -- functionality that only exists on very expensive or exclusive brands, or very new vehicles. But as long as the GPS receiver and nav system exist on a network, and multi-zone HVAC is a thing in a given chassis, then the rest is mostly just software that is free (for the manufacturer) to copy and use. Thus, Honda has been doing this stuff for at least twenty years now on fairly pedestrian vehicles.
  - ranger_danger 2y ago
    Got any sources?
    - ssl-3 2y ago
      What I have is this: The Honda factory service manual for my 2007 Odyssey touches on these operations, including diagnosing issues. It does not have an ISBN number that I can find. These systems (multi-zone HVAC, navigation) seem to have been introduced in MY 2004, remaining mostly unchanged until MY 2008 when (at least) the navigation was facelifted and the rear HVAC zone became more autonomous. Anyway, within volume 2 of that manual is this passage: i-Dual Zone and i-Tri Zone Climate Control system (With navigation system) The "i-Dual zone" climate control system automatically controls the temperature and the vent mode of the air direction to the driver's and passenger's side, depending on the angle of the sun, and the direction of the vehicle. It calculates information such as date, time, longitude, and latitude from the navigation system, as well as the radiant strength of the sun from the sunlight sensor, to determine the appropriate mode position and temperature to be directed to each side. The "i-Tri zone" climate control system is an addition of the automatic controls with the temperature and the vent mode of the air direction to the rear section to the "i-Dual zone" climate control system. ...and if I'd read something like that in 2004 (or in 2007), I simply wouldn't have believed it. Even now in 2024 it seems either a bit far-fetched or blatantly obvious, with very little middle-ground -- especially for a vehicle that can't even turn its own headlights on and off or adjust dash lighting intensity based on apparent daylight conditions (as Chevy and BMW were variously doing over a decade prior). (Other parts of the Honda manual describe the in-car temperature sensor.)

It's been since 3G that I delved into baseband specs in any depth, but I would not trust a powered up phone not to be commanded to connect to a network.

adamomada 2y ago
Couldn’t this easily be proven by monitoring transmission power from the device? There are all sorts of people who go on vacation and use the switch to avoid roaming charges. It would be plainly obvious to those people that their supposedly offline phone went online when they look at their bill. Or is there some secret apn bypass?
- Zigurd 2y ago
  Depending on how careful you are and what equipment you've got on hand, you might be able to detect that going on, but I think "easily" is a stretch. If there is a secret involved in this it would be undocumented commands sent by the network to phones that then interpret them as commands to connect to the network, plus baseband processors the periodically look for such commands. They don't radiate, so very little power is used, but they should be entirely dormant.
- ranger_danger 2y ago
  I ask this all the time but have yet to find anyone that has actually measured it. According to Snowden, basebands are still powered and operational even when the main application OS (android/ios/etc.) are shut down. And a non-removable battery sure doesn't help that. Plus, he also says that the baseband often has its own separate connections to the GPS, microphone and camera and can operate them without the application OS involved. If the baseband is still powered, I can only assume it is simply sending (or responding to) periodic commands that do not require network authorization, which could possibly still let the network know where you are even without involving any roaming charges.
richjdsmith 2y ago
Or even a phone that is "off". Newer iphones (11+) can be found through the FindMy network, even when the device is off. https://9to5mac.com/2021/07/21/ios-15-here-are-the-devices-that-support-find-my-when-turned-off/ https://9to5mac.com/2021/07/21/ios-15-here-are-the-devices-t...
- deleted 2y ago
  [deleted]

kevin_thibedeau 2y ago

Modern cars have their own internal GPS and cellular links. Even if they don't have mapping, it's probably still there, always on for tracking and compass bearing.

ssl-3 2y ago
GPS is even used for automatic HVAC controls in some vehicles. A light sensor is used determine the amount of sunlight streaming and heating the interior. GPS data is used to help calculate the angle of the sun, and determine which areas are likely to be heated the most, and thus needs more cooling. A compass can be used to make it work even when the car is stationary (when GPS heading is unavailable). A singular interior temperature sensor can be used for feedback, injecting some truth to balance things out. It may seem far fetched or even fanciful -- functionality that only exists on very expensive or exclusive brands, or very new vehicles. But as long as the GPS receiver and nav system exist on a network, and multi-zone HVAC is a thing in a given chassis, then the rest is mostly just software that is free (for the manufacturer) to copy and use. Thus, Honda has been doing this stuff for at least twenty years now on fairly pedestrian vehicles.
- ranger_danger 2y ago
  Got any sources?
  - ssl-3 2y ago
    What I have is this: The Honda factory service manual for my 2007 Odyssey touches on these operations, including diagnosing issues. It does not have an ISBN number that I can find. These systems (multi-zone HVAC, navigation) seem to have been introduced in MY 2004, remaining mostly unchanged until MY 2008 when (at least) the navigation was facelifted and the rear HVAC zone became more autonomous. Anyway, within volume 2 of that manual is this passage: i-Dual Zone and i-Tri Zone Climate Control system (With navigation system) The "i-Dual zone" climate control system automatically controls the temperature and the vent mode of the air direction to the driver's and passenger's side, depending on the angle of the sun, and the direction of the vehicle. It calculates information such as date, time, longitude, and latitude from the navigation system, as well as the radiant strength of the sun from the sunlight sensor, to determine the appropriate mode position and temperature to be directed to each side. The "i-Tri zone" climate control system is an addition of the automatic controls with the temperature and the vent mode of the air direction to the rear section to the "i-Dual zone" climate control system. ...and if I'd read something like that in 2004 (or in 2007), I simply wouldn't have believed it. Even now in 2024 it seems either a bit far-fetched or blatantly obvious, with very little middle-ground -- especially for a vehicle that can't even turn its own headlights on and off or adjust dash lighting intensity based on apparent daylight conditions (as Chevy and BMW were variously doing over a decade prior). (Other parts of the Honda manual describe the in-car temperature sensor.)