Why do we hear dialing tones during calls?

Why do we hear dialing tones during calls?

For a while I noticed a problem on different phones while having conversations with different people, without the problem being linked to a certaing mobile model. During the calls you can hear the dialing distinctive tone, just like the other person would press dialing keys during the call.

First of all, it’s good to know that the dialing sound should be heard during calls only if we have speaker mode enabled on the phone, otherwise you shouldn’t hear sounds even if the other person is hitting keys.

Every time I heard the dialing sound durin a call I checked my phone to make sure the screen is off and the other person assured me she is not pressing any key and her screen is also off.

I even thought about the person who I talk with pressing the hard keys by mistake during the call (for old phones which have hard buttons) but all of them were using smartphones without physical buttons.

It’s a strange situation which puts us in awkward positions, we’re sure we don’t press any button and the other person is also sure he/she doesn’t press any key. If we don’t know this is a common problem, then we are tempted to blame the other for hearing those sounds.

After digging into this issue, it seems that this is a common problem encountered by many users, not only iPhone users but also Android phones users, the problem is not more present on some type of phones than on others.

We can exclude the following possibilities which could lead to hearing dialing pads being hit durning our calls:

  • the other person uses an old phone with hard buttons and hits those keys by mistake;
  • the other persons do not hold the phone to their ear as they should to cover the proximity sensor and the screen remaing on and unlocked;
  • the other persons proximity sensor do not work, consequently keeping the screen on and unlocked;
  • our calls are not listened by FBI/CIA so we can hear strange sounds; I know many of you think to this possibility but even if they would bug your phone to track your calls, they would make sure you won’t notice it;
  • it’s not that old tone being heard after a minute passes present on some operators systems;

After discussing about this issue with a telecom engineer it seems that this problem is being caused by some network errors. Specifically, when someone talks and the sounds they make match certain frequencies, they trigger those dialing sounds we hear. In most cases, this problems are being caused by female voices which is at a higher intensity, which sometimes match the network’s frequency for triggering dialing tones. The “solution” is for that person to speak at a lower pitch.

It sound from sci-fi or comedy movies but it’s true. DTMF (dual-tone multi-frequency) talk-off represent those situations when the phones system recognizes the recorded sounds (most commonly, female voices) as being dialing tones. DTMF tones are emulated/regenerated by the providers and some people’s voices triggers the DTMF regeneration which leads to that dialing tone we often hear, identical to the sound of pressing a key.

DTMF talk-off problem is common not only on mobile networks (2G/3G/4G) but also on VoIP (internet telephony) networks.

Therefore, if you hear dialing tones during a call I suggest not starting an argument about this as most probably the problem being caused by the mobile network provider. For now, there isn’t a solution for this problems, the situation being dependent of the compatibility of the other persons voice pitch with the DTMF frequency of the phone provider.

Did you encounter this dialing sound during calls problem until now?


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  1. Happens all the time on a land line to me, not a cellphone. I don’t notice anything in particular that sets it off. Right now I am on hold and they are playing music but I notice nothing similar tone-wise in the music that triggers the tones, unless it is something inaudible to the human ear. As I type this there have only been songs sung by male vocalists.

    • Yes, there are some notes being hit which trigger those sounds, however it seems it’s not related only to female voices.
      This didn’t happen anymore to me for at least one year, maybe something related to my mobile provider.

  2. This problem is usually a third party on the phone listening in to your conversations. If you’ll notice, the “beep tone” happens when something is said that they want you to know they hear. In other words, the surveillance state is messing with you.

    • The explanation is the one provided in the article above, as discussed with a telecom field engineer in charge of mobile network sites.

  3. I have this same problem on my LANDLINE PHONE! This is March 2020, though. What could this be??? I’m getting a little freaked out! It’s been going on for the past 5 days

    • The problem is still the one described in the article.
      I also had this issue on my mobile phone over a year ago, however I did not have it anymore recently.

      • I don’t agree Alex, that it is caused by women’s voices. This engineer is guessing and that is a ridiculous answer. This issue went on for years, between all sexes on any phone. Started around 2015, stopped around the end of 2018, it has just started back up again in the beginning of 2020.
        If it was female voice, then it would not happen to men. And it is.
        I personally think it is related to something much darker. Like china. Don’t laugh.

        • It doesn’t need to be necessarily a woman’s voice, it just needs to reach certain notes.
          No offence, but you just want to do this a political issue, just as other people want to think it’s part of a conspiracy.
          Anyway, each person is free to believe whatever they want.

        • No offence but it’s a documented answer from a RAN engineer.
          Indeed, it can happen also with men, not only with women but that doesn’t mean it’s a ridiculous answer.
          Anyway, we are all entitled to an opinion, as am I to consider absurd your opinion regarding China listening to your calls.

      • By the way, this is happening with my landline and cell phone. Very annoying. And it happens when I talk to different people. But interestingly enough, all these people are politically conservative. I have been dealing with this for years, except between 2018 and 2020, that is the only common denominator I have found.

    • Do you hear a ring tone or a dial tone? I mean, it’s normal to hear ring tones before he answers your call, right? Or is this happening after he answered? Does this happen often or was this a one time only?

  4. For the past year, a female friend would call me from her VoIP home phone and I would hear dial tones while while she talked. When asked about pressing a key on her phone, she always replied NO. Today I have learned about “dtmf talk off” and your conclusion is correct!

    • This was a very strange thing for me before I dug a little into this issue, I always heard these dial tones while talking with my mother, but only with her.
      So I thought she was not holding the phone properly to her ear (it was a smartphone, not a phone with physical buttons), I often “accused” her she is pushing buttons with her ear but she kept saying: no, I don’t.
      It took me a while to believe her, until I investigated properly. 🙂


    • Ok, so this happen while using a landline? I’m not sure what’s causing this because the information published here refers to mobile networks, not to landlines, which is a completely different network. I suggest opening a complaint to AT&T customer service for landlines, 800.288.2020, in case you are located in the US.