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Turning off modem/Wi-Fi?

Added by Andrew R about 9 years ago

Hello,

Are there any devices where the CPU can turn off the power to the modem and/or Wi-Fi? Is this supported in the OS? It would be more useful if I could carry around a mobile phone without it talking to mobile phone towers and without it making me trackable like this:

http://www.wired.co.uk/news/archive/2013-08/09/recycling-bins-are-watching-you

Andrew.


Replies (19)

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski about 9 years ago

Replicants aims to actually provide telephony. If you don't want it, you're on your own to disable it. Possible leads are to move/remove the rild binary, but the rest of the system will probably not react well.

RE: Turning off modem/Wi-Fi? - Added by Andrew R about 9 years ago

Hi PaulK,

Thanks for your response and suggestion. Just to clarify, I guess I was hoping for the ability to enable/disable telephony with the press of a button, so that, for example, I could enable the modem if I needed to make a call. I don't own a smartphone or tablet at the moment (I have a "dumbphone" though), but I can't deny some of the non-telephony advantages of smartphones.

Andrew.

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski about 9 years ago

Ok, this is definitely not something I am going to work on.

RE: Turning off modem/Wi-Fi? - Added by Marcel Human about 9 years ago

Can't you go low brow and wrap your phone into an aluminum wrapper or a silver lined pouch?

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski about 9 years ago

What a creative workaround! It does work, but it might also be the best way to get cancer as low reception implies higher power emitted through the antenna. Bottomline: the phone will drain the battery before you know and your body will receive large amounts of energy. Perhaps not the best thing to do after all.

RE: Turning off modem/Wi-Fi? - Added by Michael S about 9 years ago

Would putting it in Airplane mode work for this?

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski about 9 years ago

Based on what I know, I cannot say that airplane mode disconnects the phone from the network. So this is not a safe workaround if you don't want to be tracked around by the phone company.

RE: Turning off modem/Wi-Fi? - Added by Michael S about 9 years ago

How about if Andrew kept his dumbphone for telephony and got an unlocked Android phone and never put a SIM card in it, so he could use all the non-telephony smartphone features without being tracked by a phone company?

RE: Turning off modem/Wi-Fi? - Added by Andrew R about 9 years ago

Hi Michael,

Thanks for the suggestion. :-) However, I have two concerns:

- Is there a guarantee that the modem wouldn't connect to mobile phone towers if the SIM is out? Obviously without the SIM it doesn't have any ID to report.

- Unfortunately my dumbphone only supports 2G, so I'd need to get another phone, one which is easy to take the battery out like my current one. 2G, by the way, is already slowly being "rezoned" to 3G and 4G, and it sounds like some countries will be phasing it out around 2017ish. I noticed that in the past year my phone reception on 2G has been reduced noticeably, and a few other people on 2G I know have noticed it as well.

I do think this will be what I will do in the future though, when I eventually decide to get a smartphone.

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski about 9 years ago

Obviously, even when the SIM is out, the modem is still running and connects to the operator's network. Now it also has to report its IMEI and the operator knows which IMEI is attached to which client, so bottomline is that the phone company can track you as well, given that you have already used your SIM on that phone.

I don't see how using another phone aside changes anything to the problem -- it can be tracked just as well (you even have less control over it than a phone running a free software operating system such as Replicant).

RE: Turning off modem/Wi-Fi? - Added by Andrew R about 9 years ago

Hi Paul, thanks for that info. I'm doing some reading up on IMEI at the moment.

Regarding the proprietary phone thing: my own use case for mobile phones is probably different to most other people's. I bring my phone around with me, but with the battery out, to university, work, etc. So if I needed to make a call, for whatever reason, I can plug in the battery. People also send me texts for some reason, although I only check the phone once every few days.

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski about 9 years ago

That would work too: carry a smartphone turned off (I can tell that the modem is actually off when the phone is turned off on the models Replicant supports) and only power it on only when you need to.

RE: Turning off modem/Wi-Fi? - Added by Andrew R about 9 years ago

That sounds much more convenient than taking the battery out, thanks for letting me know.

RE: Turning off modem/Wi-Fi? - Added by a b almost 9 years ago

Paul Kocialkowski 5 months ago Based on what I know, I cannot say that airplane mode disconnects the phone from the network.

Yes, but I guess that the phone will stop connecting to new antennas while moving so the tracking will stop after the last antenna.

Informations from "Service mode" on a galaxy S (i9000) : \*#*#0011#*#\*, it is the same code for galaxy S2 (i9100) and I think it is \*#0011#\* on the galaxy S3 (i9300) (remove the \)

With SIM card - Air plane OFF :

Basic information : UMTS = Roam(CS+PS) (or HOME depends on provider), RR State = IDLE, WCDMA 2100 ...
MM information : MM state = IDLE, Reg state = INDEP_REGISTRATION
Neighbour cell : listed cells
GPRS Information : Cell_id : xxxxxxxx, Cell.LAC : xxxx ...

With SIM card - Air plane ON - Before a reboot :

Basic information : NO SERVICE
MM information : MM state = IDLE, Reg state = USER_DETACH_PENDING (The Detach pending gives the information that maybe the phone disconnects from the network but can't get the information that it has been disconnected as it stops transmitting)
Neighbour cell : listed cells (it doesn't change, and I guess it won't vary while moving to a new location)
GPRS Information : Cell_id : xxxxxxxx, Cell.LAC : xxxx ... (it doesn't change, and I guess it won't vary while moving to a new location)

With SIM card - Air plane ON - After a reboot :

Basic information : UE YET TO CAMP
MM information : MM state = Invalid, Reg state = USER_ATTACH_PENDING (Invalid : it looks like the phone can't get any response from the network as I guess it doesn't try to connect in the first place)
Neighbour cell : The menu is unavailable
GPRS Information : Cell_id = 0, Cell.LAC = 0

Paul Kocialkowski 5 months ago Obviously, even when the SIM is out, the modem is still running and connects to the operator's network

Without SIM card - Air plane OFF : (The IMEI is reported to the provider network you selected before booting the phone and it can be another provider than yours.)

Basic information : UMTS = LIMITED, RRC State = Idle, WCDMA 2100 Band 1 ... (You get the same LIMITED message when connecting to a different network than the network having provided the SIM card you connect with)
MM information : MM state = IDLE, Reg state = INDEP_REGISTRATION
Neighbour cell : listed cells
GPRS Information : Cell_id : xxxxxxxx, Cell.LAC : xxxx ...

Without SIM card - Air plane ON - Before a reboot :

Basic information : NO SERVICE
MM information : MM state = IDLE, Reg state = INDEP_REGISTRATION (it doesn't change) (This time it doesn't try to disconnect)
Neighbour cell : listed cells (it doesn't change, and I guess it won't vary while moving to a new location)
GPRS Information : Cell_id : xxxxxxxx, Cell.LAC : xxxx ... (it doesn't change, and I guess it won't vary while moving to a new location)

Without SIM card - Air plane ON - After a reboot :

Basic information : UE YET TO CAMP
MM information : MM state = Invalid, Reg state = USER_ATTACH_PENDING
Neighbour cell : The menu is unavailable
GPRS Information : Cell_id = 0, Cell.LAC = 0

Please comment

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski almost 9 years ago

Interesting. On second thought, I think airplane mode likely disconnects the phone from the cell towers, but we didn't check it in any reliable way. I think it's likely because that's probably an obligation for FCC compliance.

It is however possible, as your research shows, that it only effectively disconnects after a reboot. (I understand cid/lac != 0 as modem still connected to the cell tower.)
Thanks for your investigation! It shows that it's likely that the modem is effectively disconnected from the network after airplane mode is turned on and after a reboot.

I have recently seen an Allwinner tablet, the Ainol AW1, that has an external modem, that one can entirely disconnect and remove from the device. That seems like the only reliable way of ensuring that it's really turned off.

RE: Turning off modem/Wi-Fi? - Added by a b almost 9 years ago

The Ainol AW1 is a radical solution and is even better than something like Huawei E5331 providing internet connection to a smartphone without modem running or a tablet without 3g connectivity as it doesn't have a battery.

I forgot to note that the investigation was done on cm 10.2.1.

The https://redmine.replicant.us/issues/825 bug made me stay on cm 10.2.1
I applied the patch you submit here : https://redmine.replicant.us/issues/711#note-15
For the moment it works again, I can change SIM, put microSD of 64 GB in the i9000 even if it should not work (it made the SIM code request not appearing / RIL crash after a boot like the https://redmine.replicant.us/issues/825 bug).

Anyway, on replicant 4.2 the service mode is not available when the airplane mode is ON : https://redmine.replicant.us/issues/831 so I don't know if the result is the same.

After a reboot, the frequency settings is forgot (Phone control, Network control, Band selection, WCDMA Band, WCDMA All for instance).

For the moment, I think you can close the https://redmine.replicant.us/issues/825 bug.

Next time I'll submit a bug using an account instead of anonymously.

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski almost 9 years ago

The Ainol AW1 is a radical solution and is even better than something like Huawei E5331 providing internet connection to a smartphone without modem running or a tablet without 3g connectivity as it doesn't have a battery.

The great thing about the Ainol AW1 is that it also provides a PCM voice interface, hence making it possible to use phone calls, what none of the external usb dongles can do.

I applied the patch you submit here : https://redmine.replicant.us/issues/711#note-15

I assume that you did that on Replicant 4.2 and that it solved that particular issue. I closed the report (as duplicate of #711).

Anyway, on replicant 4.2 the service mode is not available when the airplane mode is ON : https://redmine.replicant.us/issues/831 so I don't know if the result is the same.

I'll look into that later, it's a very minor issue. Thanks for reporting it though!

Next time I'll submit a bug using an account instead of anonymously.

Anonymous reporting is not an issue :)

RE: Turning off modem/Wi-Fi? - Added by a b almost 9 years ago

I assume that you did that on Replicant 4.2 and that it solved that particular issue. I closed the report (as duplicate of #711).

Yes, it works well for the moment, it just didn't connect one time when I disabled the airplane mode after a long time of airplane mode (still no log to provide :( )
The keyboard is a bit laggy for instance when composing a sms and playing video with VLC, even SD videos, is not possible but it is what you say in the wiki : "2D graphics, working slow"...

The selection made in service mode for frequencies doesn't stay when rebooting, I'm pretty sure it keeps the preferences in cm 10.2.1 but I didn't reflash it to try.
Do you think that this parameter could be saved when it is set in service mode in order to never connect with 2g even after a reboot?

In addition, I'm looking for a way to keep playing videos and a tablet could be the solution.

The Ainol AW1 seems interesting concerning telephony and modem unplug possibility but the display definition is really small.

You talk here https://redmine.replicant.us/boards/33/topics/3657?r=3735#message-3735 about the kindle fire first gen as a good platform for freedom but the 1024x600 definition is still small.

What tablet with display definition >= 1280 x 800 requirement would you recommend?

On i9000, could it be possible to provide a patch for video acceleration like for the wifi or is there a lot of modifications in the code that makes it impossible?

RE: Turning off modem/Wi-Fi? - Added by Paul Kocialkowski almost 9 years ago

The selection made in service mode for frequencies doesn't stay when rebooting, I'm pretty sure it keeps the preferences in cm 10.2.1 but I didn't reflash it to try.
Do you think that this parameter could be saved when it is set in service mode in order to never connect with 2g even after a reboot?

Please open a new bug report about that, it doesn't seem to be normal behavior.

What tablet with display definition >= 1280 x 800 requirement would you recommend?

You have to understand that the bigger the display definition is, the slower the device will be, unless it has a real amazingly fast CPU.

On i9000, could it be possible to provide a patch for video acceleration like for the wifi or is there a lot of modifications in the code that makes it impossible?

Not currently, video decoding acceleration relies on other proprietary bits. I already know about these issues, (mostly, video decoding at all is broken, outside of VLC).

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