I usually don't answer unknown numbers. Few days back i got couple of calls from unknown numbers and i didn't answer it. That evening i had contacted one of my lady friend and the next day i got a call from that friend but when i answered it, to my utter surprise it was an operator calling for a confirmation for the service i recently applied. They disguise their call with my friend's number and name. Is that possible.

  • 2
    it's possible that your phone(is it a smartphone?) has some bug and showed a wrong caller number... that being said, there are countries in which telecom operators are obliged by law to store call conversations and keep them for a minimum of 6 months, it doesn't matter if you buy a pre-paid SIM card or you're on contract, the terms of service are considered agreed as soon as you activate the card(after switching the phone with the card in, it hits the nearest tower).
    – user17464
    Commented Apr 24, 2013 at 6:04
  • @computersaysno And thats why I take phones from dumpsters every few months and gove fake details. Yay
    – NULLZ
    Commented Apr 24, 2013 at 8:41
  • as a side note, in my country the operator saves all calls and logs for 1 year, but, listening to millions of calls is just impossible! for English language that speech can be converted to text, converting all sounds to plain text is also very hard task because it requires too many process...
    – Akam
    Commented Apr 24, 2013 at 11:12

3 Answers 3


It is possible for operators to fake their caller ID's although I have not heard of them doing it for phone calls in practice.

Certainly they are aware of the phone numbers you call, but considering how many calls would go through their systems each minute, I would say that the answer to your title question "Do telecom operators listen to every phone call?" would be a resounding no. It's just not possible without a huge amount of manpower. There are ways to automate the process using keyword recognition etc but it's not practical to have an actual person listening to every call.

Which carrier are you with/where are you located? We might be able to find some further information on any practices like this.


Telco operators do not listen to every call.

This is basically resource limited as "telco-switches" work hard enough as is just passing signalling and internal processing. To further answer, not even agencies/organisations listen to every call. They tap what they know they want to in advance (called LI or Lawful Interception).

Operators that operate legally doesn't fake called IDs, which is obviously possible. Even online services can offer you this through some SIP interconnect to a poor operators network. The challenge is a lot of specifications doesn't actually include any requirements for treating these calls, eg. passing an international ISDN exchange (Q767).

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    While I cannot confirm or deny this claim, he states that every call in the US is recorded and can be accessed at a later date & time. Take it as you will, but I thought it might be relevant. huffingtonpost.com/2013/05/07/tim-clemente-fbi_n_3229478.html and some interesting discussion on the matter: yro.slashdot.org/story/13/05/05/2329240/… Commented May 16, 2013 at 12:04
  • Neither can I, not regarding the US anyhow, but generally all signalling is dumped and kept for some time in any network. The difference here is actually listening to calls or recording them, a quite tedious and process heavy thing todo for any system. Signalling contains the basic information about a call, not the audio stream itself. Commented May 16, 2013 at 12:15

Carriers by themselves don't listen (because they won't gain any money from that) nor record (that would require quite a bit of storage space and infrastructure), but given that they control the network and there's no end-to-end encryption in conventional calls (GSM encryption is only between the phone and cell tower), they definitely can (and will) provide the audio stream of the call when asked by law enforcement (or if one of their engineers is bored and wishes to listen in; this is no joke, it happened to Google, it can definitely happen to your carrier as well).

On the other hand, what they definitely do is log the calls, that is, the tower you're connected to while calling, the date/time, the destination number, the IMEI of the device user while calling, the ICCID of the SIM card used in the calling device, and possibly other scary stuff. The destination carrier does the same, as they're required by law to do so in most countries (at least for the call target and duration, the "other scary stuff" isn't yet mandatory).

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