Can mobile device manufacturers tell a user’s phone number from the SIM card?

Dr.sunil V June 30, 2014

Can mobile device manufacturers know a user’s phone number from the SIM card inserted in device?

  1. Howard B
    July 1, 2014 at 9:10 pm

    The SIM card (Subscriber Identity Module) stores the connection information, including the phone number and subscription status. The manufacturer would have no information, it's the *carrier* (AT&T, Verizon, T-Mobile, etc.) that have an interest in whether a phone is active or not.
    Every phone has an unique IMEI number (International Mobile Equipment Identity) as well, which is what Verizon uses (on SIM-less phones) to provide identity information; that's why you can swap a SIM card from one phone to another (with compatible cellular radios) but can't do this with many Verizon phones.


    • Drsunil V
      July 21, 2014 at 4:39 pm

      Thank you very much. Please tell , is IMEI number independent of sim card?

    • Susendeep D
      July 22, 2014 at 2:42 pm

      IMEI is used as a unique identity for phones.This has nothing to do with your SIM.

    • Dr.sunil V
      July 24, 2014 at 5:03 pm

      Can manufacturers know IMEI number and from IMEI can user info like name , number be accessed?

    • Howard B
      July 27, 2014 at 6:24 am

      @Dr.sunil V: Manufacturers assign the IMEI number at the factory (it's the phone's serial number, in essence; it uniquely identifies the device), but MANUFACTURERS don't have anything to do with the phone directly. The phone's CARRIER (the phone company that you buy minutes/airtime/data from) knows everything you've provided - name, address, etc. - if you have signed a contract; pay-as-you-go companies like Tracfone, Net 10, BasicTalk (essentially all the same company, America Movil) generally don't ask for anything that you didn't provide when you set up the phone (email).
      Obviously, the carrier assigns the phone number and MUST know that.

      I don't see all the confusion between phone "manufacturers" and "cellular providers" I've seen in this thread - does a car manufacturer (GM, Chrysler, Mercedes) know the license plate number you put on the vehicle? They put the VIN number on the car - identifying a particular vehicle - but the DMV (where you REGISTER the car) and insurance company know who registered it and connect the VIN to the driver. It's much the same with IMEI, phone numbers, and SIMs (on devices that have SIM cards).

    • Dr.sunil V
      July 27, 2014 at 7:32 am

      Thanks for taking interest and putting time in this topic. Do you mean that IMEI number cannot enable manufacturer to access SIM card info ( mobile number and name ) via internet

    • Howard B
      July 27, 2014 at 7:41 pm

      @Dr.sunil V: Why would the manufacturer want to access a device they've already sold to a carrier, and then was sold to you?
      You have several layers to go through: The manufacturer builds a phone and assigns it an IMEI number. The carrier (whether it's AT&T, Verizon, T-Mobile, Orange, O2, or China Telecom) buys the phone, assigns it to a user who buys minutes and is assigned a telephone number (either buy putting a SIM in it or associating the IMEI number with an account), and the person starts using it.
      Seeing as there's no phone number assigned to the phone while it's sitting on a store shelf, the manufacturer doesn't know what phone number is going to be on what phone. Therefore, the manufacturer will have to find a way to associate the IMEI number with a phone number without being noticed...remember, the carrier handles *all* the traffic; why would the manufacturer ever "talk" to the phone via the Internet? That kind of traffic would arouse suspicion, as security analysts love to analyze the traffic to and from the devices they work with - you've no doubt heard of Apple's "diagnostic capabilities" that were just disclosed.
      No, I don't think *manufacturers* get any information from the phones they've sold. It's the *carriers* that associate an IMEI with a phone number. Any attempt for the *manufacturer* to send traffic over a *carrier's* network (or someone's WiFi) would be noticed.

  2. Susendeep D
    June 30, 2014 at 3:24 pm

    Try he following Android app SIM Card

    I've checked my friend's Android phone with SIM inserted and when I gone to About Phone,it doesn't displays phone number.

    • Drsunil V
      July 21, 2014 at 4:37 pm

      I understand, but query is different

  3. Hovsep A
    June 30, 2014 at 2:31 pm

    why would manufacturers get your personal info, it is up to your carrier to protect you

    • Dr.sunil V
      July 3, 2014 at 7:20 am

      I understand. Please note that query is not whether manufacturers like to get mobile number but whether they could get mobile number from sim inserted into the model?

    • Hovsep A
      July 16, 2014 at 6:42 pm

      well if the manufacturer implemented some hardware/software so to get information from the some information from the sim card then anything can be possible. But there are rules and the manufacturer cant bypass that.

      In the sim card a cryptographic algorithm is used to protect authentication of the subscriber, there is another cryptographic algorithm to protect the phone call over the air interface.

    • Dr.sunil V
      July 27, 2014 at 7:26 am

      Once on purchasing a phone , if a user automatcially receives sms from manufacturer company then what it implies

    • Hovsep A
      July 27, 2014 at 9:04 am

      well maybe you have some applications installed (made by the manufacturer or by agreement) like social applications that is connecting the user to the manufacturer? Or the user opened an account in the manufacturer website like for guarantee activation and added the phone number there?

  4. Oron J
    June 30, 2014 at 2:09 pm

    Phone manufacturers know nothing about you, since they only make the phones and sell them on via vendors. The phone number is provided by the mobile provider (a telecom company) - the company that provides the SIM. The SIM is essentially an ID card, identifying the user, so yes, your mobile provider should be able to tell your phone number by reading your SIM.

    If you are asking about a data-only service, though (e.g. for a tablet or laptop), there may not actually be a phone number associated with the SIM.

    • Dr.sunil V
      July 3, 2014 at 7:23 am

      Thank you very much. Yes , the phone manufacturers do not know about buyer of the model. But is it possible for manufacturer to retrieve buyer's mobile number ( say , through built in default software system which can relay the number from sim card onto the manufacturer through internet )

    • Oron J
      July 3, 2014 at 9:38 am

      Theoretically, yes. Manufacturers can plant any malware they like into phones. Indeed, there have been cases in the past where computer hard drives were infected with a virus at the factory (as I understand, this was done by rogue workers rather than by company policy). However, there's little reason for phone makers to do this. They make the devices, but they don't control who the device is sold to, and they don't have privileged access to the networks, which are run by carriers. If spyware of the sort you suggest was installed, it could be detected quite easily by the carriers, who would also be able to tell where the traffic is going to and nab the offending company.

      In other words, the question should not be "is it possible" (almost anything is), but "why would they do that"?

    • Drsunil V
      July 21, 2014 at 4:38 pm


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