[HN Gopher] The IMEI Code: Your phone's other number
___________________________________________________________________
The IMEI Code: Your phone's other number
Author : shortformblog
Score : 261 points
Date : 2024-04-29 18:39 UTC (2 days ago)
(HTM) web link (tedium.co)
(TXT) w3m dump (tedium.co)
| BuildTheRobots wrote:
| Couple of thoughts
|
| > The combination of the ICCID and the IMSI basically tells the
| mobile network, "hey, this person paid for a plan."
|
| As far as I remember, the ICCID never actually appears in
| standard network messaging. It might be possible for the network
| to request it, but it's not part of a standard 2/3/4/5g attach.
|
| The piece seemed to miss two major uses for the IMEI (or I missed
| it when reading), which were working around vendor bugs and
| allowing emergency calling.
|
| Radio firmware and state machines have always had weird bugs, and
| even when it conforms to standards (some of which are extremely
| interpretable), does very weird things in the real world. Pre-
| smartphone, being able to update phone and radio firmware was
| extremely rare, so it was common for the networks instead to
| implement workarounds on a manufacturer or handset basis. Having
| a hardware ID that identified this was extremely useful.
|
| GSM (and onward) actually supports a handset attaching to a
| network, even without a SIM card, for the sake of emergency
| calling. It needs some form of unique identifier for this to
| work. As much as it could (potentially, entirely redefining the
| stack) generated UUIDs, it makes some sense for these unique IDs
| to persist across roaming/sessions/reboots.
| heilhippo wrote:
| https://arcelect.com/GSM%20Developer%20Guide%20-%20GSM%20AT%...
| lxgr wrote:
| These are AT commands, which specify (one way of)
| communication between a modem or phone and a PC, or maybe a
| smartphone OS and a baseband.
|
| The phone/baseband doesn't talk to the network in AT
| commands.
| heilhippo wrote:
| In theory it doesn't, in practice it does.
| lxgr wrote:
| No, it doesn't.
|
| AT commands also don't make it onto your phone line,
| after all. They're for communication between a host and a
| modem/baseband, not between a host and another host or
| even two modems.
| sumtechguy wrote:
| The AT commands are usually used at call establish time, but
| can be used at other times to query the status of the modem.
| AT commands never go into the network that is a different set
| of standards. They are only used on the modem in your phone.
| If you can get on the right serial pin on the modem you can
| issue AT commands to the modem and it will do all sorts of
| interesting things. Different companies have their own
| standards.
|
| Think of the AT commands as just telling the modem to put
| itself in a particular mode or go do something. After that
| the serial bits will do different things or output different
| things. It does not specify what will be said in the data
| mode (that is the GSM/CDMA/LTE/RS232 standards and a
| different part of the modem). Just that the modem will do
| particular things.
|
| Take for example this old command ATDT,,5555555 That tells
| the modem attention, go into output DMTF sounds, wait 2
| seconds, wait 2 seconds, output the DMTF tones on the speaker
| line for 5555555, then wait for a sound of response on the
| receiver and negotiate the highest both ends can talk using
| the S registers to decide what to do. But the AT commands do
| not go over the wire. They are purely modem commands. The
| modems in many cell phones still basically do this. But just
| with different commands and different registers. There is
| nothing stopping the modem from sending more AT commands to
| the other side though but that would be something in the
| standards to declare.
| lxgr wrote:
| > As far as I remember, the ICCID never actually appears in
| standard network messaging.
|
| Yeah, that would be the IMSI (which a given SIM card can have
| multiple of, e.g. for switching to a more beneficial home
| network while roaming!)
|
| The ICCID is useful for identifying a given physical SIM card
| (e.g. so that the phone can link a given user-selected profile
| name to it/the associated phone line for a "preferred line for
| contact" indicator in dual-SIM phones), and probably also as an
| identifier when dynamically assigning a new IMSI over the air.
|
| > for the sake of emergency calling
|
| The IMEI can indeed be an identifier of last resort for
| emergency calls. I wonder if some countries use it to block
| abuse/spam calls to emergency services, or more importantly,
| why some others aren't?
|
| In Germany, for example, SIM-less emergency calls are no longer
| possible, supposedly due to many people calling the local
| emergency number to test whether a used phone is in working
| condition without inserting a SIM card... I don't know what
| they're doing with the IMSI in that case, and if it's locking
| these callers out, why they can't do the same for the IMEI.
| tjohns wrote:
| At least in the US, the 911 infrastructure is dated.
|
| In older systems, your caller ID is sent using in-band DTMF
| tones, which are decoded by the dispatch computer.
|
| On newer E-911 systems they get some additional digital
| address data from the telephone network, but the record
| format wasn't designed with VoIP or cellular in mind. So in
| those cases, the telephone network sends a virtual number and
| the dispatch computer does a seperate out-of-band lookup with
| the VoIP/cellular company using that number as a key to get
| your location.
|
| The whole emergency calling system is layers upon layers of
| hacks. While they can bolt additional functionality on if
| they're creative, it's more likely a given feature is _not_
| implemented. There's a good chance that by the time the call
| gets to dispatchers, the IMEI/IMSI isn't displayed anywhere
| and they just see a random virtual number.
| sfx2000 wrote:
| Gosh, yes it's a bit of a mess...
|
| The PSAP (E911 end point) likely will receive an MDN/MSISDN
| (10 digit number you dial for NANP networks) - this is so
| they can call back if the call is dropped.
|
| E911 is a special service, so in the case of
| deactivated/missing SIM cards, the carrier assigns a
| temporary MSISDN for duration of the call when the UE exits
| E911 mode - there are actually of regulatory and carrier
| requirements around E911 mode.
|
| E911 Phase 2 required not only the DN, but also if possible
| the location of the device - whether thru Cell Base Station
| Triangulation (if possible) or GNSS with a LAT/LONG based
| on coarse/fine location info.
|
| In any case, as @tjohns mentions, IMSI/IMEI are not
| typically used outside of the servicing network.
| lxgr wrote:
| Good point, and implementing a "this IMEI calls 911 to ask
| for the time of day every hour" block on the side of the
| networks seems risky as well, so I get how it might not be
| that helpful.
|
| But then I wonder why having an IMSI (as far as I
| understand, the SIM can be deactivated, foreign etc., i.e.
| it doesn't need to actually register to the network)
| improves this in Germany?
|
| Maybe German authorities just hope that having to insert a
| SIM might deter people, since SIMs are perceived as being
| personally identifiable more than just phones without a
| SIM?
| jfoutz wrote:
| Huh. That's a think I've had vague notions of, but you've
| made pretty explicit.
|
| Technology under pressure looks a lot like biology.
| jimbobthrowawy wrote:
| I have heard of people calling emergency numbers to test if a
| phone is working, but never a country making that impossible.
| Here, I had always assumed that repeated nuisance callers
| would be investigated to see if there's an actual problem,
| and charged with a crime if they're doing it for no good
| reason.
|
| Always thought it would make more sense to have a dedicated
| "test number" for this purpose. Probably with some rate
| limiting.
| amatecha wrote:
| A lot of telcos used to have phone numbers you could call
| that would just say the number you're calling from (like
| with a computerized voice). I forget what this was called,
| but it was talked about in phreaking community or so on.
| Not sure if these "caller identifier" phone numbers are
| still around today though.
| miki123211 wrote:
| They're easier to make than ever, all you need is Twillio
| and a bit of Python code. There are quite a few in the US
| alone, both provided by carriers as well as enthusiasts
| and other companies in the industry.
| bsagdiyev wrote:
| 800-444-4444 still works. Even starts with "thank you for
| calling MCI"
| razakel wrote:
| They're called ANACs - automatic number announcement
| circuits.
| amatecha wrote:
| Ah yeah that's right, thanks!
| BayesianDice wrote:
| BT in the UK has 17070 which tells you the number and
| lets you do tests like the "quiet line test". Handy when
| working out what was going on when I moved into a
| property with no live phone service (so no normal
| outgoing calls), lots of phone extension sockets, and (I
| discovered) _two_ landlines coming in...
| kevvok wrote:
| > Radio firmware and state machines have always had weird bugs,
| and even when it conforms to standards (some of which are
| extremely interpretable), does very weird things in the real
| world. Pre-smartphone, being able to update phone and radio
| firmware was extremely rare, so it was common for the networks
| instead to implement workarounds on a manufacturer or handset
| basis. Having a hardware ID that identified this was extremely
| useful
|
| Now that it's common for devices to be updated regularly, they
| will typically send an extended form of the IMEI to the network
| called the IMEISV, which is the same as the IMEI except the
| final check digit is replaced with a two-digit code indicating
| the current software version (SV = Software Version).
| lloydatkinson wrote:
| Only two digits? What could possibly go wrong... again.
| rohansingh wrote:
| Probably not a lot. It needs to have a fixed length on the
| wire, and having 100 updates to the radio firmware for any
| given model of handset... not likely?
| londons_explore wrote:
| The fact the IMEI is generally not editable seems like a massive
| privacy hole.
|
| Just let people edit it. Then I can be someone new every day and
| nobody can track me.
|
| Mac address randomization does that for wifi. Now do the same for
| mobile networks.
| kevincox wrote:
| I really want mobile networks to accept their role as dumb data
| pipes. I should be able to just provide a password or
| certificate and connect. No IEMI, no SIM.
|
| And while we are at it stop tunneling my data back "home" when
| I travel. I don't want increased latency.
| londons_explore wrote:
| And while we're at it, how come if I have a phone without a
| sim I can't at least navigate to a carrier webpage to buy an
| esim?
|
| The phone could pop up a menu saying "Here are the available
| networks", and you pick one, connect and it says "Welcome to
| AT&T, enter credit card number here", and you type a number
| and hit OK and you're connected.
|
| Oh wait - just like Wifi!! Why are mobile networks so far
| behind?
| btgeekboy wrote:
| Kinda like this? https://en.m.wikipedia.org/wiki/Apple_SIM
| kbolino wrote:
| How would a networking stack with no hardware addresses even
| work? The next hop needs a way to reach back to you, before
| you can negotiate anything fancy like passwords or
| certificates. Even IPv6 SLAAC starts with a hardware address.
| londons_explore wrote:
| rand()?
| kbolino wrote:
| A MAC address is 48 bits and an IMEI is about the same
| entropy-wise. That's not nearly enough room to avoid
| duplicates (even SLAAC requires duplicate address
| detection, and IPv6 has a lot more bits to work with).
| You'd need a whole new layer 2 protocol, though to be
| fair you might be able to strip it down to just doing
| collision detection/avoidance and leave addressing up to
| layer 3 with IPv6, but that's not going to be any kind of
| backwards compatible or interoperable.
| boznz wrote:
| Surely the uniqueness is only required at the bottom end
| of the stack before the first 'router' ie the cell tower
| baby_souffle wrote:
| > Surely the uniqueness is only required at the bottom
| end of the stack before the first 'router' ie the cell
| tower
|
| Not if you need to send a message to $thatUniquePhone.
|
| Over simplifying considerably, but if a land line places
| a call to a mobile, the "220-1234 calling for 220-7890"
| message enters the network. The `220-7890` phone number
| needs to map to the unique modem address so you can look
| up which tower the call setup data should be sent to. If
| - by sheer coincidence - I also have your MAC address and
| am attached to a tower 3 states away... which tower(s) do
| you forward the call setup data to?!
| vdqtp3 wrote:
| > which tower(s) do you forward the call setup data
|
| Whichever one has most recently communicated with the
| user in question (based on the credentials or certificate
| provided, in the original example)
| kbolino wrote:
| Assuming something like VoIP is in use, you reach other
| devices with their IP addresses, not MAC addresses.
| thaumasiotes wrote:
| As far as I know MAC addresses are never used to route a
| message to a particular recipient. They're used so that
| devices that overhear the message, but aren't the
| intended recipient, can ignore that message on the honor
| system.
|
| If you have a wired connection, this makes the MAC
| completely superfluous. The concept is sort of still
| valid for wireless connections (or of course for "wired"
| connections where you have multiple devices physically
| connected by the same wire, a bus, where the concept
| originated). It should be rethought.
| londons_explore wrote:
| Yes - the whole MAC/ARP/IP parts of the typical IP stack
| are a legacy mess and should be sorted out.
| kbolino wrote:
| Yes, but you could have hundreds of thousands of devices
| connected to that tower in a dense metro area. Even a
| single hardware address collision would result in both
| devices being unable to reliably reach emergency
| services.
| kevvok wrote:
| The use of IPv6 in cellular devices is specified by RFC
| 7066. When a device first registers for a data connection,
| the network provides an interface identifier to use for the
| lifetime of the registration, which is guaranteed not to
| conflict with the one used by the router. The network also
| allocates a /64 prefix exclusively for use by the device.
| These two things allows the device to perform SLAAC for
| link-local and routable addresses without needing to do
| duplicate address detection.
|
| It's also worth mentioning SLAAC does not strictly require
| a hardware address to function. For example, Apple devices
| implement newer standards from IETF to generate random but
| stable addresses that don't reveal information about the
| hardware addresses
| (https://support.apple.com/guide/security/ipv6-security-
| seccb...)
| ixwt wrote:
| > And while we are at it stop tunneling my data back "home"
| when I travel.
|
| Oddly enough, I found this to be a plus when I traveled to
| China for work. My data was unmolested by the Great Firewall
| of China. I was able to get on websites with my mobile data
| that I couldn't when using wifi in the hotels.
| techsupporter wrote:
| > And while we are at it stop tunneling my data back "home"
| when I travel. I don't want increased latency.
|
| You might not, but a whole lot of customers who aren't as
| technically sophisticated did. When T-Mobile first started
| doing included international data roaming, they didn't tunnel
| back. That caused a lot of confusion from customers who
| didn't realize why stuff they expected to work, like checking
| their bank balance, didn't. (It also made throttling speeds a
| lot more difficult.)
|
| So to fix that, T-Mobile tunnels you back to a few endpoints
| in the States. Banking apps are generally happy, as are
| Netflix and Spotify. Most customers are happy because their
| phone "just works" the same as it "always has".
|
| For those of us who want to avoid the latency, we get a local
| SIM for data (if possible).
| hunter2_ wrote:
| This is interesting. I use Verizon Wireless from the US,
| and when traveling abroad on their travel pass (roaming),
| some large multilingual websites serve me the local
| language instead of English, on sites that serve me English
| when I'm at home. My browser (Accept-Language header) is
| configured for only English. I always decline location API
| browser popups.
|
| The only thing I can think of, assuming they tunnel as you
| describe, is maybe I first loaded the site from local WiFi
| instead of mobile data, at which point I was redirected (to
| a localized subdomain that doesn't redirect back) or got a
| cookie or something, which lingered as I continued without
| WiFi.
| jhoechtl wrote:
| CB radio has you covered
| gsich wrote:
| Only if you also change your SIM every day.
| londons_explore wrote:
| As a man who currently has 13 esims in his phone...
| mytailorisrich wrote:
| There is no privacy concern, really, as this is unique to the
| device, not subscriber, and only shared with the network
| operator, who obviously already "tracks" the subscriber through
| the SIM , which contains the subscriber identifier (IMSI).
|
| On the other hand, the IMEI in principle makes tracking and
| disabling of stolen devices easy.
|
| By the way, in the UK it is actually an offence to change the
| IMEI [1]
|
| [1] https://www.legislation.gov.uk/ukpga/2002/31/section/1
| toast0 wrote:
| The IMEI also allows a network operator to track a device
| across multiple sims. And I think it's also shared with
| roaming operators if roaming happens.
| jimbobthrowawy wrote:
| IIRC when you put a SIM into a new device for the first
| time, part of the tower auth includes the IMEI of the
| previous device you used it with also.
| NoImmatureAdHom wrote:
| "There is no privacy concern, really..." Except for the
| network operator, who needs to track a _SIM card_ not a
| phone, but who can track you across networks and SIM cards if
| he has the IMEI. There is no reason the IMEI needs to be
| stable.
|
| The network operator does NOT need to know who you are, even
| if you live in a repressive country that mandates tying ID to
| mobile phone lines. Get a SIM card in person and top up in
| cash, or use a virtual credit card, or pay in cryptocurrency
| for an eSIM, or get a subscription in a less oppressive
| country and roam.
|
| Invisv is a great suggestion.
| least wrote:
| This is 100% a privacy concern if you're dealing with state
| level actors.
| ale42 wrote:
| They can track you with or without the IMEI. Next
| identifier is the IMSI read from your SIM card and I guess
| you're not replacing it every day...
| least wrote:
| Disclaimer: used to work in SIGINT, so please treat
| anything I say about this with appropriate skepticism.
|
| There are people that for various reasons do cycle out
| their SIM card frequently as a means to avoid tracking.
| This is ineffective. Changing the IMEI/discarding devices
| entirely is more effective.
| ale42 wrote:
| But if you change IMEI and use the same SIM card, you're
| still trackable as if nothing changed, right? The IMSI
| would be the same. I guess you need to change both at the
| same time...
| ikekkdcjkfke wrote:
| Dudes have been driving around with fake base stations,
| rare, but has happened. Only sent spam sms messages with
| links but could be expanded with buying data from data
| brokers. A really serious crime though
| xw38011 wrote:
| I would think state level actors have enough tools to deal
| with this issue. If nothing else they could go the old
| fashioned way and just, you know, follow you.
| least wrote:
| It isn't usually the goal of SIGINT to only collect data
| about a target's location nor are targets always that
| easy to follow.
| hughesjj wrote:
| Any immutable id is inherently a privacy concern. Network
| operators are ISP's, and ISP's have been known to do things
| like hijack unresolvable DNS entries to a search page with
| ads. The network operator knows who you are and what imei was
| associated with your account.
|
| I wouldn't be surprised if there were some 'ghost'/virtual
| profiles associated to an imei similar to how Facebook would
| do with the like button
| mytailorisrich wrote:
| Well, there's your phone number. Networks and law
| enforcement only need that.
|
| Existing privacy level is adequate for members of the
| public. Anyone who actually, really requires more either
| has state agencies resources available or is being wanted
| by state agencies...
| ementally wrote:
| You can, but it is not that easy and you also need to change
| your IMSI.
|
| https://invisv.com/pgpp/ for IMSI (not available worldwide)
|
| https://github.com/srlabs/blue-merle for IMEI, a nice guide
| written by them explaining how it works
| https://raw.githubusercontent.com/srlabs/blue-merle/main/Doc...
|
| You can follow this thread for more info
| https://discuss.privacyguides.net/t/cell-towers-tracking-net...
| hinkley wrote:
| I think I'm more concerned with the fact that the carriers know
| the IMEI of phones and claim that they can do nothing about
| stolen phones. That was the beginning of the end of my
| infatuation with the mobile space.
|
| I should have been well positioned for early retirement during
| the early smart phone gold rush but was just so put off by the
| Ma Bell feeling of the mobile industry that I had exited before
| most people had even entered.
| fencepost wrote:
| _I think I'm more concerned with the fact that the carriers
| know the IMEI of phones and claim that they can do nothing
| about stolen phones._
|
| Maybe once upon a time, but I'm pretty sure stolen devices
| can be blacklisted from networks these days.
| nolan879 wrote:
| Carriers have been blacklisting IMEIs for at least 10+
| years. Since phones tended to be carrier-locked back then
| you couldn't go to a new carrier without being in good
| standing to get your device's unlock code from the old
| carrier. Now that devices are available unlocked by
| default, it is probably harder since it would require
| carriers to communicate IMEIs?
| ale42 wrote:
| Not sure, I think that there are international lists of
| stolen IMEIs. Maybe it's just in Europe, though.
| wrboyce wrote:
| ~15 years ago the blacklists were certainly shared within
| Europe, but there was an intercontinental trade of
| blacklisted phones from Europe to Africa (and, if memory
| serves, Asia).
| hinkley wrote:
| I looked it up. US Carriers were forced by the US
| government to start blacklisting them in the final months
| of 2012. They didn't do it voluntarily.
|
| Australia had been doing it since 2003. IMEIs have been
| around for 30 years? Everyone having a cellphone is still
| a relatively recent phenomenon, but according to Pew 80%
| of American adults had cellphones for several years
| already before carriers were forced to deal with stolen
| ones.
| lesuorac wrote:
| I believe the point is that they could've been blacklisted
| from the start and instead carriers would just put up their
| hands say "there's nothing we can do" despite there being
| something they can do.
|
| It's like when your apple laptop gets stolen and then
| starts using your applecare support and apple won't help
| you get it back.
|
| Of course, if you decided not to pay your phone bill I'm
| sure that device would get blackslisted real fast.
| londons_explore wrote:
| In Kazakhstan, when a phone is used on a mobile network for
| the first time, the IMEI of the phone gets locked to that
| mobile network and that sim card. When you buy the sim card,
| they photocopy your passport/ID card.
|
| No other sim will work in it until you take _that_ photo ID
| /passport to the mobile companies office to have it unlocked.
| The photo id (even if expired) becomes the unlock code for
| the phone.
|
| Made phone theft drop to pretty much zero.
| medo-bear wrote:
| > Made phone theft drop to pretty much zero
|
| Use a nuke to kill a fly?
| 6th wrote:
| It was the only way to be certain.
| _heimdall wrote:
| The ends always justify the means.
| sambazi wrote:
| i imagine that phone theft is more common in poorer
| regions
| madeofpalk wrote:
| In Australia, you can report your phone as stolen and it
| becomes IMEI blocked, not able to be used on Australian phone
| networks.
|
| https://amta.org.au/lost-and-stolen-mobiles/
|
| https://amta.org.au/check-the-status-of-your-handset/
| sambazi wrote:
| sounds like a dos vector. is there a lot of abuse of this?
| tessellated wrote:
| sounds like considering linking to a social security
| number would be a good idea.. any reasons this ain't
| commonplace?
| mynameisvlad wrote:
| The article literally talks about blacklisting and has a
| photo of what a blacklisted phone shows when this happens.
| hinkley wrote:
| And what time frame did I apply for when I exited mobile?
| mynameisvlad wrote:
| Your entire comment makes it sound like your gripes are
| current issues, not those that you experienced decades
| ago in a completely different mobile landscape.
|
| You continually use the present tense when the
| argument... just doesn't apply anymore.
|
| > I think I'm more concerned with the fact that the
| carriers know the IMEI of phones and claim that they can
| do nothing about stolen phones.
|
| This is not a fact anymore.
| apienx wrote:
| SMS specifications include "Type 0" messages, also known as
| Silent SMS. These messages don't trigger any even on the phone
| when received, but they do send back an ACK that includes IMSI
| metadata. Silent SM, are literally defined in the RFC and
| primarily used to covertly track user locations without
| judicial oversight.
|
| GSM, SS7, etc. are massive privacy holes _by design_.
| ParanoidShroom wrote:
| They are primarily used for configuring your visual voicemail
| lol. Stop the hyperbolic statements.
| walterbell wrote:
| Can they be disabled/blocked on the device, when not needed
| because the user has disabled "visual voicemail" with their
| carrier?
| skyyler wrote:
| https://www.heise.de/news/Zoll-BKA-und-Verfassungsschutz-
| ver...
|
| Not sure where you get your information, but these are
| routinely used by police to covertly track targets.
| lmz wrote:
| Just because they are routinely used for such does not
| mean it is their _primary_ purpose.
| fsckboy wrote:
| when we know that govts want this capability, when we
| know that govt regulators are in the same room with
| telcos when plans are being drawn up, when we know govt
| uses these capabilities routinely, why would you doubt it
| was there for that purpose? isn't this a good time to
| round up the usual suspects? If the govt intervenes to
| get this capability and also declares that this should
| not be the _primary_ purpose, I guess that would make it
| a secondary purpose? OK, I feel better now, phew!
| squigz wrote:
| Could you elaborate on this? What is a 'visual voicemail'?
| What would a 'silent SMS' have to do with that?
| advisedwang wrote:
| Visual voicemail is where an app on your phone can show
| you a list of voicemails and you can click a button to
| play them, as opposed to you having to dial a number to
| access voicemail (the old "press 2 to hear the next
| message" stuff).
| lxgr wrote:
| I'm not sure if Visual Voicemail really uses silent SMS,
| but even older phones had a series of indicators such as
| "voicemail waiting", "message waiting" etc. which the
| network could control via binary SMS payloads.
|
| By sending one that clears all of them in a network that
| doesn't use them (or sending one equivalent to the
| current state for one that does), you can achieve the
| outcome of initiating SMS-MT (mobile-terminated) delivery
| to a given ME (phone) without any user notification.
|
| SMS delivery by necessity involves paging the device,
| revealing its location at a finer level (base station
| instead of paging area).
|
| So I wouldn't say silent SMS were designed as a spying
| tool, but they're one out of several ways to silently
| "ping" a phone and force it to communicate with the
| network without having to wait for it to cross location
| area boundaries, get or make a call etc.
| chenxiaolong wrote:
| Visual voicemail is when the dialer app on your phone can
| show the list of voicemails similar to how you would see
| your email inbox. You can directly play the voicemail
| messages and depending on the device/carrier, there might
| also be a text transcription of the audio.
|
| Many carriers implement this via "silent SMS" + IMAP (the
| same IMAP as for emails). The device will send an
| activation or status message to the carrier's visual
| voicemail number and the carrier will respond with an SMS
| containing the IMAP credentials.
|
| The version of this I'm familiar with is T-Mobile's old
| CVVM protocol. During initial setup, the device will send
| a text message containing "Activate:dt=6" to the number
| 122 and T-Mobile will reply with (in decoded form):
| pw_len=4-9 vs_len=10 u=<IMAP username>
| pw=IMAP password> rc=0 st=R
| ipt=148 srv=e7.vvm.mstore.msg.t-mobile.com
| lang=1|2|3|4 g_len=180
|
| If visual voicemail is already enabled, then sending the
| "Status:dt=6" SMS to 122 will also result in the same
| reply. Putting the credentials in an IMAP client will
| work and it doesn't have to go over the phone's cellular
| connection. You can even use curl: curl
| -v imaps://<USERNAME>:<PASSWORD>@e7.vvm.mstore.msg.t-mobi
| le.com/
|
| T-Mobile has deprecated this protocol though. New
| activation messages will fail with a blocked status:
| rc=0 st=B srv=vvm.mstore.msg.t-mobile.com
|
| T-Mobile replaced this CVVM protocol with two HTTP based
| protocols: "mstore" (used by OEMs like in the dialer app
| on Google Pixels and OnePlus devices) and "cpaas" (used
| by T-Mobile's first party visual voicemail app). I've
| been working on an open source client for mstore for use
| with open source Android OS's, like GrapheneOS.
|
| In case anyone is interested, the vvmd wiki (visual
| voicemail implementation for Linux phones) has
| information on how several carriers implement VVM:
| https://gitlab.com/kop316/vvmplayer/-/wikis/Visual-
| Voicemail.... AT&T's is especially nasty.
| WirelessGigabit wrote:
| I remember using one of those dongles with a SIM card that
| you could talk to with an API and use that to send flash SMS.
| Full screen warnings to friends. Only option was 'OK' and the
| text was gone afterwards.
| ale42 wrote:
| My old Nokia C2-01 allows sending them from the menu ;-)
| ian0 wrote:
| Silent SMS is an incredibly convoluted and impractical way of
| trying to figure out someones location.
|
| The whole purpose of mobile networks is to track a devices
| location (so you can route data to/from it!). Of course its
| easy to do it if your the operator or someone who has
| compromised it.
| miki123211 wrote:
| They're not privacy holes by design, but they're not privacy
| friendly by design either.
|
| When these things were designed, privacy wasn't really a
| concern and wasn't really thought about in the way it is now.
| The assumptions were very different, it was assumed that only
| large and trusted companies could get on SS7 and those would
| play by the rules, or else face the wrath of the government.
| Now, a small carrier in a third-world country that routinely
| violates human rights can get that access.
| breakfastduck wrote:
| they WANT you to be stuck with it because then they can track
| you no matter what
| ale42 wrote:
| Mobile phones are a massive privacy hole. Almost by definition.
|
| And smartphones 10 times more (or more, depends on how many
| apps you installed, almost all of them include some sort of
| trackers).
|
| IMEI is (almost) the last of my privacy problems.
| lxgr wrote:
| Definitely don't let people edit it. iOS and Android don't
| allow picking your own MAC address for good reasons - people
| would inevitably pick 12:34:56, 00:00:00 etc. and cause
| problems for themselves and others.
|
| To increase privacy, either randomize it (but make it much
| longer at the same time to avoid collisions) and/or remove it
| from as many signalling contexts as possible and keep it as a
| device-local identifier only (which then probably also doesn't
| have to be unique across manufacturers).
| hwbunny wrote:
| There were a lot of chinese made keiser phones that allows you
| to edit all the phone/sim related identifiers. Sadly they were
| discovered and rooted out of the amazon marketplace.
| ementally wrote:
| You can use https://github.com/srlabs/blue-merle if you want to
| change your IMEI
|
| >The blue-merle software package enhances anonymity and reduces
| forensic traceability of the GL-E750 / Mudi 4G mobile wi-fi
| router ("Mudi router")
|
| >Mobile Equipment Identity (IMEI) changer
|
| >Media Access Control (MAC) address log wiper
|
| >Basic Service Set Identifier (BSSID) randomization
|
| >MAC Address randomization
| soylentcola wrote:
| Looks like it only works on their portable router (a separate
| device) unless I missed something. A sort of proxy for your
| phone I guess?
| sfx2000 wrote:
| I don't recommend mucking about with the IMEI, as you risk a
| collision with another device that is already using that IMEI -
| IMEI's are supposed to be immutable.
|
| I realize that there are some Modem OEM's that might allow the
| IMEI to be "adjusted", but proper modem vendors will not allow
| that AT command.
| KenArrari wrote:
| If someone knows your IMEI can they track you?
| kbolino wrote:
| Not from the other side of a wide-area network, but if they are
| continuously in close proximity to you, or can effectively
| monitor everywhere (three letter agency), then yes. Of course,
| there are other ways to track you.
| harshaxnim wrote:
| Can you elaborate on what you meant by trackable when they're
| "continously in close proximity to you"?
| p_l wrote:
| Snooping, or hijacking, the radio pathway between you and
| your network operator.
| aspenmayer wrote:
| https://en.wikipedia.org/wiki/IMSI-catcher
| wiml wrote:
| If they can listen to the radio traffic between your phone
| and the cell tower, that is.
| lxgr wrote:
| I think this is only true for older mobile networks. In 4G
| and 5G, I don't think the IMEI is part of any unencrypted
| radio message anymore.
|
| Even the IMSI is only used when absolutely necessary, i.e.
| for the initial attachment procedure when cold starting a
| device or entering a new routing area; after that, it's
| replaced by an alias called TMSI to make tracking phone users
| a bit harder.
|
| New Android versions will supposedly have a switch in their
| settings to show a warning every time the IMEI or IMSI is
| transmitted in plantext [1].
|
| [1] https://cs.android.com/android/platform/superproject/main
| /+/...
| spiesd wrote:
| I'm interested in the general thrust, but this article is sloppy
| at best.
|
| > Check digit: The final digit is essentially used to validate
| the prior 14 digits with an algorithm. Similar digits exist in
| other types of identifier codes, such as the Universal Product
| Code (UPC) and the International Standard Book Number (ISBN). The
| algorithm that the mobile industry uses, the Luhn algorithm, is
| also used for social security numbers and credit card numbers.
|
| No, just no. SSNs (in the US) don't have check digits.
|
| Also:
|
| > Then there are network identifier numbers--the MAC address
| bestowed upon you by your WiFi network or mobile provider
|
| Huh? This nonsense ("bestowed upon") serves only to confuse. This
| is bad tech journalism: it fails to inform the masses, and is
| transparently worthless to experts.
| toxik wrote:
| Many non-American SSN systems do have check digits.
| cesarb wrote:
| The Brazilian CPF (our equivalent to the SSN) goes up to
| eleven (literally) by including not one, but _two_ check
| digits; IIRC, the first one (the tenth digit) is computed
| over the first nine digits, and the second one (the eleventh
| digit) is computed over the first ten digits.
| dhosek wrote:
| The geographic aspect of SSNs no longer applies either. My kids
| have SSNs that start with different digits than my own which
| was assigned under the old regime where the first digit
| indicated where the SSN was issued.
| xjay wrote:
| Android defaults to sending the IMSI (SIM ID) to Google.
|
| > SUPL is used as part of the A-GPS (Assisted GPS) system to get
| a faster Time to First Fix. The problem is that Android's
| implementation automatically sends the IMSI (ID of the SIM card)
| to the SUPL provider for no apparent reason. And because Google
| is the default provider it's a big breach of privacy.
|
| https://github.com/Magisk-Modules-Alt-Repo/supl-replacer
|
| https://en.wikipedia.org/wiki/Assisted_GNSS
| sambazi wrote:
| and then proceeds to download a blob to be interpreted by the
| firmware over plain http
| tredre3 wrote:
| The S in SUPL stands for secure, it's ssl encrypted. Whether
| or not the implementation is good, I don't know, but saying
| it uses plain http is patently false.
| SubzeroCarnage wrote:
| I document this more in depth here
| https://divestos.org/misc/gnss.txt
| ale42 wrote:
| From the article: it will generally start with
| a 35, which is unused as a country calling code
|
| It's "unused" because several country codes _start_ with 35:
| Ireland, Portugal, Luxembourg, Iceland... (This doesn 't mean
| that phones are actually manufactured there... I have a phone
| with an IMEI starting in 354 and it's definitely not manufactured
| in Iceland...)
| lxgr wrote:
| Yeah, they seem to be confusing that with IMSIs or ICCIDs,
| which are indeed namespaced by mobile country code and
| international calling code respectively.
|
| Based on what other commenters have already pointed out, this
| seems to be a quite sloppily researched article.
| misstuned wrote:
| This is interesting - I hadn't noticed this, but my Chinese
| (Xiaomi) phone indeed has an IMEI starting with 86, which is
| China's dialling code. Perhaps a coincidence.
|
| The ICCID starts 8944 - not sure of the significance of the
| 89, but 44 is the UK, where my SIM card (and me) comes from.
| ale42 wrote:
| 89 is the MII (major industry identifier) according to
| ISO/IEC 7812 (https://en.wikipedia.org/wiki/ISO/IEC_7812).
| First digit 8 includes the telecom industry.
| gandalfian wrote:
| Also a rare UK success story in brute force lawmaking. People
| used to hack phones IMEI all the time, lots of utils available.
| Then anything relating to changing an imei was heavily punished
| and it all stopped. Nobody would host a utility or a guide or
| even mention it on a forum. If you did mention it you were
| banned. It was almost instant.
| ykonstant wrote:
| That doesn't sound good at all.
| Biganon wrote:
| "Success story" does not imply that the greater good was
| successful
| smcin wrote:
| ... mention it on a UK forum, European forum or any forum?
| chirau wrote:
| Is there any entity or procedure that actually proves what a
| phone is what it claims to be?
|
| Unfortunately, neither IMEI, Serial Number or a combination of
| both can assert this.
|
| I bought a Samsung S24 a week ago off Facebook Marketplace. It
| was in the box and everything. I cross checked both the IMEIs and
| also the Serial Number with the #06# test. I even checked them
| online. Did all the tests, _#0_ # and even downloaded Samsung
| members. Paid for the phone, convinced it was a genuine one.
|
| Upon registering it and using it, it becomes very clear the phone
| is fake and is at best a clone. The camera is nowhere near the
| S24 and does not have the features. It heats up after charging
| and does not keep charge. It runs slower than a 10 year Android
| once you are signed it.
|
| when you run diagnostics, it shows all the specs of an S24 Ultra.
| How do I know this? I went and got another S24 Ultra from the
| store and they are worlds apart.
|
| So my question is, if you are buying a phone from a reseller or
| someone, is there any way of definitely asserting whether it is
| authentic?
| yardstick wrote:
| This is typically where consumer rights laws come into play and
| a key advantage of buying first hand from a "real" business
| rather than an individual or third party. At least there you
| have someone you can easily hold to account.
|
| You need to price in the risk factor when purchasing where such
| legislation doesn't apply or isn't easy to enforce.
| tschwimmer wrote:
| I'm sorry that this happened to you. The debugging and tear
| down sound like they would make for an extremely interesting
| blog post though. I encourage you to write it up and post it
| here - I'd definitely read it.
| miki123211 wrote:
| Some YouTuber bought one of these (not specifically an S24)
| and found a hidden app that "told" the phone what it should
| be.
|
| You could set how much RAM you wanted, how much storage, what
| CPU and so on, and then that info would be shown in all the
| "about" screens. They went to a few Tb of ram if I remember
| correctly.
|
| Changing any of these parameters didn't have an impact on
| what the phone could actually do, just to be clear.
| chirau wrote:
| Would you have a link to the video by any chance? I would
| like to invest some time in showing how to detect and
| remove said app
| sfx2000 wrote:
| The carrier can ID the device type by the radio layer itself at
| the PHY layer.
| chirau wrote:
| How would I go about doing this?
| numpad0 wrote:
| Anything on the display or reported by Linux Kernel can be
| faked, so no.
| sfx2000 wrote:
| Interesting thread - as someone that used to be in carrier
| space...
|
| IMEI - we only really cared about the TAC prefix, as this
| identifies the device type, which is mapped to capabilities for
| services.
|
| IMSI - this is usually in the SIM card (UICC), and mapped out
| specifically within the uSIM/SIM application inside the card.
| This is aligned with the Billing/Rate Plan for services that the
| subscriber is set up with.
|
| TMSI - this is usually what the network uses to page you and also
| deliver singaling over the NAS via the SGs interface for devices
| that do not support IMS/VoLTE
|
| ICCID - this ID's the card itself, for SIM cards, it always
| starts with 89 as this designates the card as telephony related
| as a physical UICC - remember, there are other types of UICC's
| such as CHIP based Credit Cards, which start with a different
| number.
|
| MSISDN - this is the number that you dial and send SMS to - in
| legacy systems, it can also be referred to as the MDN
|
| Fun Fact that was skipped in the article - IMEI's that start with
| 99 are special, as these indicate that the Device is both
| GSM/UMTS/LTE and CDMA/EVDO capable, and generally those IMEI's
| will align closely with the CDMA MEID's, but they were not
| required to. The "99" range wasn't just Apple, but was used in
| the early days of dual-mode across most vendors as it helped
| facilitate session handovers from C2K to any 3GPP based service.
| For C2K, on the IMSI front, most devices would use IMSI_T (True
| IMSI based on the SIM card IMSIef) but some used IMSI_M which was
| based on the legacy MIN.
|
| Legacy - there is the ESN in CDMA, but this is very legacy, and
| was largely superseded by MEID - for Legacy Support, pESN could
| be derived from MEID, however at the high risk of collisions...
| thedougd wrote:
| Many a year ago, when the iPhone was new and Android was on
| version 1.6. Sprint offered the SERO plan, an unlimited plan for
| friends and family. When smartphones hit, they would no longer
| allow the SERO unlimited plan to transfer to the new phones.
|
| The HTC phones had a Qualcomm radio that, with the right tooling,
| one could write all 0s to the IMEI (or the CDMA equivalent)
| register. Then you could write any IMEI to the register. That
| worked well for a few years.
| sfx2000 wrote:
| SERO was one of the Sprint Rate Plans, the other was the
| Pioneer Plan for early adopters on SprintPCS
|
| HTC got into a bit of trouble with the carriers on the whole
| IMEI/MEID rewrite mess at the end of the day. With Qualcomm,
| that was an NVITEM that was supposed to be read-only.
| m463 wrote:
| didn't I read recently about some manufacturer that shipped
| many of its phones with the same imei?
|
| EDIT: "Over 13,000 Vivo phones found to be using same IMEI
| number"
|
| https://www.techradar.com/news/over-13000-vivo-phones-found-...
| mannyv wrote:
| I remember some telco guy saying "the IMEI is unique until it
| isn't."
|
| We always wondered if you could crash part of a cell network by
| dropping in 8192 phones with the same IMEI. Everyone needs to
| deal with non unique identifiers, but the question is how many do
| they expect?
|
| FYI this is a problem on Ethernet, when you get boards that
| haven't been initialized. Things don't like multiple MAC
| addresses with 0s.
| username135 wrote:
| I have been looking for information like this for a while. Thank
| you!
|
| Follow up, does the IMEI number get broadcast when you connect,
| or is it a searchable bit of information accessible by apps, et
| al?
|
| Im wondering how anonymous you can be if youre making all the
| right privacy moves, but your phone is still essentially giving
| you up because your IMEI number is traceable back to you.
| ztetranz wrote:
| Fun fact: Lots of cellular modem/routers have the easy ability to
| change IMEI. Doing so is a fairly common practice in the rural
| internet community. i.e., those using cellular for their internet
| access either because cable / fiber or an official cellular
| option like T-Mobile home internet is unavailable or they're
| mobile in an RV.
|
| These people are not trying to do anything particularly nefarious
| but they do it so that they can use a phone or tablet plan in a
| router. Unlimited or high GB plans for routers and hotspots are
| expensive and there are not many options.
|
| There are lots of reasonably priced, easy to get unlimited phone
| and tablet plans but if you put a phone SIM in a router it might
| work for while until the carrier detects that you have the SIM in
| an unauthorized device. The "solution" to that is to activate on
| a spare phone and then change the router IMEI to match the phone.
| Don't use both devices at the same time. The carrier now thinks
| the router is a phone.
|
| The legally of it is somewhat unclear so it's talked about
| quietly on various forums using words like "magic configuration",
| "giving your router an identity crisis" etc.
|
| It's a bit of a cat and mouse game because IMEI is probably not
| the only way to identify an unauthorized device but so far it
| seems to be the main way.
| sambazi wrote:
| glorious
|
| reminds me of changing mac address to get around data caps in
| the student dorm network
| xattt wrote:
| Or getting online with an Ethernet network that refuses to
| connect with an unauthorized MAC.
| ale42 wrote:
| Same but for airport wifi time limits... had to use Linux
| because the Windows drivers the laptop didn't allow manually
| setting the MAC address.
| vel0city wrote:
| I remember back in the 00's on AT&T getting an unlimited data
| plan addon for a dumb phone was like $15/mo or something while
| adding it for a smartphone was like $40 or more. They would
| enforce it by checking your IMEI and seeing if it was one of
| the smartphones they sold.
|
| Buying an unlocked phone of a model AT&T didn't sell seemed to
| never trigger the "you're using a smartphone" check. Fun times
| with some cheap 3G back in the day.
| grayfaced wrote:
| In 2004, I was doing something similar on Tmobile. Flip
| phones internet was cheap. Could tether it via a cable to
| laptop and I also used an external antenna to improve signal.
| I would leave it up overnight downloading videos on p2p. I
| was in Army barracks at time and no one else had decent
| internet.
| hiatus wrote:
| What are some of the devices that allow you to easily change
| the IMEI?
| ztetranz wrote:
| I have one of these
| https://www.amazon.com/gp/product/B09NDDH6S8 which is easy to
| change. You still need some knowledge to run some AT commands
| on the modem. It's easy to find the instructions online and
| it can be done from the web based admin. Yes, they have AT
| commands like old dialup modems.
|
| Anything from https://thewirelesshaven.com. I have an old one
| of their routers and the latest firmware literally has IMEI
| as a textbox in the admin.
| ale42 wrote:
| Passive TCP/IP fingerprinting might tell a lot about the
| device. You could probably easily tell apart an iPad and a
| router. But if IMEI checking catches 95% of plan cheaters, it's
| probably not worth implementing more checks (more checks = more
| cost and infrastructure to maintain, is it cheaper than the
| lost revenue?).
|
| This said, I find it insane that there are such plans. The cost
| of a connection should be the same whatever the device behind
| is.
| ztetranz wrote:
| I think there's lots of ways they could tell if they really
| wanted to. One way is simply looking at the traffic. "Why are
| apps on your Android phone accessing Windows update
| servers?". Of course a VPN can solve that and the game
| continues.
|
| Something interesting might happen next week. T-Mobile Home
| Internet is not supposed to be moved from the registered
| address but until now that has not been enforced. It's quite
| popular with RVers. They just announced a new "Away" plan for
| $160/mo that you are allowed to move compared to $60 for the
| normal home plan and, not surprisingly, it seems like they're
| about to start enforcing the geo-restriction on the home
| plan. This apparently uses GPS in the device. Well, I hear
| that a lot of people are using the home internet SIMs in
| other devices with the IMEI set. This is because there are
| much better devices with external antenna ports etc. These
| might be in trouble if they don't respond to the GPS request.
| solidsnack9000 wrote:
| It is a minor part of the article, but I'm surprised they
| introduced it only to get it so wrong.
|
| _The U.S. Gun Control Act of 1968, among other things, requires
| traceable serial codes on guns, something that has become a key
| element of forensic ballistics. In some circles, this is seen as
| controversial, as highlighted by a case involving "ghost guns"
| that the Supreme Court is hearing this session._
|
| First of all, serial numbers don't have much to do with forensic
| ballistics. Generally, in forensics, investigators are comparing
| items in their actual possession -- shell casings, bullet
| fragments, and weapons recovered from the scene of a crime or
| from a suspect. Serial numbers don't help with that.
|
| Serial numbers are useful in investigating gun trafficking --
| it's actually very similar to the example of car theft that the
| author presents early in the article.
|
| Regarding the "this is seen as controversial", that is a claim
| that is absurd beyond belief. What is at issue in the case is
| _when_ the requirement to serialize adheres and to what it
| adheres. That is a complex issue. A gun is made of dozens of
| components. Many are tiny with small surface areas, like springs
| and pins, and many are replaced over the life of a gun, so
| serializing them would (a) be ineffective and impractical and (b)
| could actually confuse the identity of the gun.
|
| So when do we serialize and what do we have to serialize? For a
| long time, the settled practice in the industry has been that
| there is _one_ component that is "the firearm". This part
| generally is large, is subject to low mechanical stresses, and
| can be expected to last the life of the gun. This is generally a
| part called the "receiver" or "frame".
|
| If the receiver is ever damaged beyond repair, regardless of the
| state of the other parts, then a "new" firearm has to be created
| and serialized. Although the barrel, trigger, &c, are all the
| same, it is a different gun now.
|
| This system has actually worked pretty well and has allowed for
| relatively robust tracing of stolen guns and guns found in
| investigations of international arms trafficking.
|
| Collections of parts that make up an incomplete gun are of two
| kinds -- if the receiver is in that collection, the collection of
| parts is a firearm and has to be sold according to the rules
| governing transfer of a firearm; if not, it isn't.
|
| A receiver or frame starts life as a large block of metal or
| plastic. So what if we sell people a parts kit where we have
| every part of the gun except the receiver, and also an
| appropriately sized block of metal or plastic? Nothing in this
| combination has to be serialized and it is not a firearm.
|
| Until recently, this was not really an area of much activity
| because, while a receiver is subject to low mechanical stresses,
| that is in relative terms -- relative to other parts of the gun.
| It is nevertheless a component that takes a fair amount of
| machining and finishing to get made. What brings us to the "ghost
| guns" discussion and the Supreme Court case linked in the
| article, is the degree to which home manufacturing with light
| tools has improved in recent years. It is actually possible now
| to make a pretty good receiver without a machine shop. Some
| people came up with a business of selling people almost complete
| guns, with a block of plastic or metal and some jigs that allowed
| them to readily complete the receiver. This is an edge case and
| it will take some thought to establish when, exactly, we apply
| the rules regarding serialization. The people making blocks of
| plastic probably will not be required to serialize all blocks of
| plastic simply because they are potential firearms (along with
| potentially being many other things); but the people buying the
| blocks of plastic to put into kits that they then sell to others
| in order to make guns probably will be seen to have created a
| "constructive firearm" and so will be required to serialize them.
| 0898 wrote:
| I prefer to buy second hand iPhones for my family, and usually
| use Amazon. But the last couple of iPhones haven't been able to
| connect to the cellular network at all.
|
| Digging into it, it seems they've been IMEI blocked - i.e.
| reported stolen. Sending them back to Amazon is always such a
| pain because it means a visit to the post office.
| amelius wrote:
| Instead of calling it "IMEI Code", perhaps we should call it the
| "IMEI Cookie".
| Havoc wrote:
| Anybody know how frequently these get transmitted?
|
| Phones seem to switch off wifi regularly for energy savings, so
| not particularly useful for detecting iphones at home for home
| presence automations
| Someone wrote:
| "Other" isn't really correct, is it? The IMEI is your phone's
| number, your phone number isn't tied to a phone, but is your user
| name/chat handle with your provider.
| calrain wrote:
| Is it possible to record IMEI codes of phones around your
| location?
|
| Say... to help identify if a specific phone comes around, or what
| phone/s were around when a break in occurred?
| eknkc wrote:
| If you buy a phone in Turkey, it's IMEI is registered to a gov
| authority and you can use / transfer it as you wish.
|
| If you happen to buy one from another country, it will be locked
| after 60 days of use and no carrier will connect it after that.
| You can use your passport to to prove that it was not imported
| commercially but you brought it with you and register it. For
| $1000 (yeah). And it is locked to your ID. Can't transfer it to
| someone else.
|
| IMEI cloning from an already registered donor phone was a thing
| and maybe it still is but as far as I can tell, high end phones
| pretty much lock it tightly.
|
| BTW, this also affects a lot of other stuff. Can't buy a gps dog
| tracker from amazon. Can't buy a gsm module for your arduiono
| etc...
|
| My car has a connectivity system where it provides internet to
| the in car infotainment system and also allows me to open doors
| etc remotely. It only recently became operational when the
| distributor finally managed to register the IMEI numbers. A lot
| of companies do not bother (Mercedes, BMW etc are equipped with
| similar systems, not operational)
| vegetablepotpie wrote:
| > Can't buy a gsm module for your arduiono
|
| What do you mean by that? Ostensibly I can.
|
| https://www.adafruit.com/product/2687
|
| Note: it's on back order, but in theory I would be able to buy
| a GSM module for my Arduino.
| circuit10 wrote:
| From reading the message, it wouldn't work in Turkey because
| the IMEI is blocked
| anticensor wrote:
| it is a whitelist, not a blacklist
| meeby wrote:
| They mean you can buy the adapter, but it won't work in
| Turkey as the EMEI isn't on the official allowed list and
| isn't registered.
| AceyMan wrote:
| as a native English speaker I transparently read that
| as,"there's _no point_ in buying a GSM module [...] ", but I
| can see how others might possibly be tripped up by that
| construction.
| eknkc wrote:
| Oh this is interesting. I'd think it is implied enough that
| there would be no confusion.
|
| My native Turkish might be seeping through though. Thanks
| for the heads up.
| BXLE_1-1-BitIs1 wrote:
| The instructions to changing firmware on a tablet before
| repartitioning had me backing up and restoring IMEI and MAC
| address etc.
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