Level 1

20 points

DTMF Tone on IOS 13 issue

There is a new feature on IOS 13 on my iPhone X (I went into an Apple store and tested in on several phone models all using IOS 13) that shortens the DTMF tone. So when you press a number in a automated system it has a short beep instead of a long tone. Every number on a keypad has a different DTMF tone that is how automated systems recognize that you have pressed 1 for english. I have an iPhone 8 with IOS 12 and IOS 12 still has the long DTMF signals, so this is an IOS 13 issue The short beep is not an issue when I am dialing out, but is an issue when I am trying to accept collect calls through a 3rd party, automated system when I press zero to accept the call it drops it because the DMTF tone is too short for the automated system to capture it. Anyone else having this issue.?

iPhone X

Posted on Oct 19, 2019 2:07 PM

Top-ranking reply

BoldAsLove420

Level 1

10 points

Posted on Jun 12, 2020 8:09 AM

FIX: switch to 4G by turning off LTE

I can say with a high level of confidence that if your having this issue it's not the iPhones fault. This is almost definitely an IVR setup/development issue.

I develop and integrate IVR systems and have had this issue personally. It's an issue with how the IVR is handling the touch tone, its not an issue with the iPhone. We had this issue on our IVR systems and resolved it, but since you can't control the IVR systems here's what you can do to get it working: turn off LTE and use 4G when calling into an IVR that doesn't recognize your DTMF's.

I was able to record the DTMF's that the IVR received from the iPhone (note: this does not mean the iPhone created this, it just means that by the time it got to our system it was represented as seen; there can be intermediary systems that affect this).

Results:

When using and iPhone on ATT LTE the touch tones look PERFECT. I mean perfect. They are to the spec, exactly. I've never seen any other touch tone come through so perfect. They were exactly the length required, were spaced out exactly as needed, etc etc. When switching to 4G the perfect touch tones degraded but looked like any other ones we get on the system. The touch tones on LTE did not work, 4G did.

In our case the touch tones were being sent to a speech recognizer that then sends back DTMFs if it detects them. Once we changed our setup to recognize OOB touch tones it worked (it didn't have to send them to the speech recognizer, the driver that we have recognized them correctly and we just changed the driver to send us the touch tones instead of relying on the speech recognizer). There are reasons for having the IVR setup this way and in some cases the fix won't be as simple as it was in ours.

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124 replies

Dogcow-Moof

Level 8

36,827 points

Dec 31, 2019 5:19 AM in response to 2point5

The VoLTE setting seems to indicate that cellular providers are somehow mangling the DTMF tones when it is enabled.

Sep 2, 2020 6:45 PM in response to JeremyLeeDiaz

Yes... we had to revert one of our iPhone 10’s back to the 8 so we can open the gate... all other versions of the iPhones work and so do the androids.

tc-syr

Level 1

4 points

Apr 18, 2020 4:20 AM in response to janiesue1

DTMF tones and the space between them is symmetrical i.e. if the tone lasts 50ms then the “space” between it and the next tone must be 50ms

DTMF tones are the result of of two tones played simultaneously the result is a harmonic or compilation of the two. The resultant tone is what is detected by the receiving end. ANYTHING that disturbs this resultant waveform distorts the tone and it is not recognized. Background noise, white noise of sufficient amplitude, the rustling of your headset can “disturb” the integrity of the tone. Apple is correct in that 50ms is the standard design value for tone duration/spacing

Having said all that it would be in everyone’s best interest to have around 80ms of tone/spacing in order to RELIABLY deliver at least 50ms to the receiver.

Nov 25, 2020 6:55 AM in response to sl985

Well, we are a multi generational iPhone family, all in ATT. The older devices (before 10) all operate our gates and other security IVR’s. The 10s and above do not. Even on speaker, the tones don’t play.

Dogcow-Moof

Level 8

36,827 points

Nov 30, 2020 10:16 AM in response to LeroyEdwin

Once again, please read the information here:

https://discussions.apple.com/thread/250764240?answerId=253371576022#253371576022

Apple cannot control what your cellular carrier decides to do.

You may be able to work around this by disabling LTE, but I realize that's a pain.

Dogcow-Moof

Level 8

36,827 points

Dec 2, 2020 3:59 PM in response to JCARPENTER67

So if it's the phone, given DTMF packetization occurs in software, have you not updated the "old phones that work" to iOS 14? That's the only way I could account for a difference.

Once again, DTMF tones are not sent as sounds on VoLTE, they are sent to the cell tower which passes on the instruction to play "touch tone 7" to the equipment sending audio to the IVR.

As LTE packets are encrypted, only carriers or someone with LTE test gear would be able to answer the question of whether newer versions of iOS aren't sending enough packets to encode longer tones.

ricsem

Level 1

8 points

Nov 25, 2020 11:53 AM in response to Win W

All I know is I updated my iphone83 to latest software OS 14.2 from older OS w/ short tones and the long tones work. Apple seems in denial

Dec 2, 2020 1:33 PM in response to Win W

Hi,

Therefore did you try to switch on speaker right before responding to the IVR instead of turning off voLTE?

Oct 19, 2019 2:11 PM in response to sl985

The short tones should work with any properly designed IVR system. In general short tones are better, because when the signal is weak a long tone may be broken up by the network and will appear to the IVR as multiple presses of the same key. I haven't noticed any issues so far myself.

2point5

Level 3

973 points

Nov 22, 2019 5:49 PM in response to sl985

Absolutely agree with other comments that this is unacceptable. I communicate with an IVR system through my internet provider and the call centre is on the other side of the globe. These shortened tones result in the IVR simply not recognising the selection that I make.

Apple needs to fix this YESTERDAY.

Dec 14, 2019 12:21 AM in response to sl985

The hilarious part in all of this: Apple's own IVR system is unable to pick up the tones. So when Apple support calls you, you are unable to press "1' to accept the call.

So much for that theory about properly designed IVR systems.

Jan 15, 2020 2:23 AM in response to sl985

properly designed IVR System is not the actual standard over the world. Most IVR System are dated and cannot recognize short DTMF.

The choice to use also long DTMF tones would be greatly appreciated.

rc707

Level 1

4 points

Apr 2, 2020 12:04 PM in response to sl985

Have been having this issue for a few months since a software update. The new short tones do not work with the vast majority of services that I use. I was surprised to see this has been a known issue since October 2019 and yet is not fixed. This has now become a huge issue since we depend on remote services more now due to the pandemic. Apple: I strongly recommend that you add a setting to adjust or work-around this issue ASAP.

Apr 18, 2020 5:45 AM in response to tc-syr

Agreed. However, Apple is not recognizing this inefficiency as a problem or the DTMF, as a whole, an issue. They still are asking me to call AT&T and blame them. This is from their Tier 3 engineer!!!! In order to even look at the issue, they’re asking that AT&T open a ticket first for them, in the background, which would flags as an issue for both companies to resolve between Themselves (Apple and ATT)....

Dogcow-Moof

Level 8

36,827 points

Jun 9, 2020 4:03 PM in response to TallCat

Right now you are complaining about something unlikely to change anytime soon, so you won't be buzzing anyone in until your community fixes their system.

In the mean time, you can let Apple know of your desire here:

Feedback - iPhone - Apple

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DTMF Tone on IOS 13 issue