Hi, while waiting for my Brax3: I plan to use it without SIM. As I understand since IMEI is tied solely to the hardware (a digital fingerprint for the device) and indeed you can call emergency numbers without SIM, I guess phone pings BTS when turned on. How do I prevent this? I wish not to have any GSM connectivity, as it wasn’t a phone at all. Any tips on first use to prevent “reporting” to GSM tower?
There is some way to deactivate emergency calls, search the forum, it has been discussed it the past, in fact it’s somewhere in the settings.
I would advise to let the phone be able to do emergency calls because you’ll regret it if you find yourself in a critical situation.
It’s not about calls emergency or any other. It’s about IMEI number that is your device’a fingerprint. “No SIM” without deactivating GSM capability makes NO SENSE. And I will be stil able to dial 112 (I’m in Europe) as any other number, just not via GSM network.
I’ll look for solution, thanks for answer!
You can go to airplane mode to disable the modem as much as possible.
What do you mean to dial 112 but not on GSM?
When you dial 112 the modem logically will try to find the easiest way to do it.
The phone certainly can sense passively the cellular towers but it hasn’t any reason to communicate since it doesn’t want to synchronize, the process of logging to the tower is very complicated and it has to acquire a time slot.
Maybe wiping your IMEI numbers off your phone? Write them down first. They are on the box it came in. SP Flash by default is in Download mode. Change that to format. I don’t think anybody here has done that on purpose, but there are some threads here talking about SP Flash and IMEIs.
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Confirmed-no IMEI means no emergency calls. Write those IMEIs down first!
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Ow, that may be crucial: so when switched on phone with SIM card (or eSIM) acts differently then without any??? I couldn’t find definitive answer…
I don’t know about “passive” in GSM range… I’m afraid that with or without SIM the phone will “login” to GSM network with IMEI. The “112 call” was just an example of situation when IMEI (phone’s “fingerprint”) will be exposed to GSM network as I know emergency calls work always.
And making calls without SIM is different subject. VoIP etc., it’s not an issue.
THANKS!!! Actually since my only concern is privacy, I don’t want my phone to be “logged” by GSM providers as I don’t intend to use GSM at all, I guess “airplane mode” would be enough. It should prevent any GSM connectivity while using WiFi.
Apparently changing IMEI is illegal in Poland even if you do not use GSM network. Privacy is all I need, I don’t intend to do anything against the law.
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For tuning the emergency calls and information search “emergency” in the settings, you can deactivate it, it has been discussed in the past here in the forum.
You can find the SS7 specifications from the GSMA online. The modem first detects the SIM and asks for the PIN if it’s set. If you unlock it it reads the settings and the cryptographic keys and will try to authenticate to some tower according to some complicated settings inside the modem that describe the priority of the tower to be selected, those can be tuned with AT commands.
It can locate the towers passively, if it’s in airplane mode it will certainly not send any signal because the purpose of this mode is to not congest the towers in case of fast moving vehicles like airplanes.
There is also no need to send any message and congest the towers just to say hello for no reason. The time slot mechanism is very delicate and it can be saturated easily, this could be a form of attack to the cellular network.
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Thanks again, I think I’ve got everything now. Cheers!
I’m not real sure how triangulation tracking with cell towers works. I would think they wouldn’t track a phone with no Sim card. Maybe they use IMEIs too. My phone has neither and should be invisible!
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Triangulation needs the least 3 antennae receiving the same signal to estimate the cross-section of at least 3 circles, if the phone doesn’t emit signal they can’t do it.
In any case even one antenna is enough to know that you are somewhere around, other more sophistcated methods use reflections too like passive radars.
I can’t understand what you are saying, write again differently.