DTMF Tone on IOS 13 issue

as a retired telecom engineer for 35yrs i would like to suggest that Apple use a slightly longer DTMF tone as many IVR's look for a minimum of 50ms tone duration before "recognizing/validating" the tone. My personal experience after 10yrs as the CallCenterGuy, is 80-100 ms should be sufficient as it is neither too long or too short for most well designed systems. This is mostly due to ambient noise issues (background noises) or poor quality connections. Please consider an option to allow/tune for longer tones and do your homework/product testing BEFORE releasing any new IOS to the real users. THANKS!

This trick worked on my iPhone11 (iOS13.3) to solve the issue.

Previously i was able to navigate through IVRs in this same phone. But since last 1 month i was not able to do so. Must be a problem cropped up in the recent updates of iOS.

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.

Turning the VoLTE off fixed the issue for you? For about 6-8 weeks now I haven’t been able to receive 3rd party calls that I need to press 0 to accept and I’m ready to pull my hair out. Was on the phone with technical support for 2.5 hours today and they couldn’t tell me anything!

Has anyone figured out a real fix to this issue? I don’t have those setting to do the work around in my iPhone 11. It’s crazy this is still an issue and very frustrating that someone is blaming the IVR systems.

There is no real fix until Apple increases the duration to 70/80ms. I have shared my thoughts with Sr. Tech support. You might get some relief if you turned OFF wifi calling. At 50ms there id no room for error detecting the tones. 70/80ms is a very useful value for Apple to consider.

I spoke to the Sr tech support yesterday who seemed to be confused at first. He didn’t want me to elaborate on the problem any further and cut me off from giving him further information as to where he can find others having the same problem. After almost an hour on the line he said he was sending the issue over to the engineering department and would get back to me in 1-2 days. I’ll update if he can get anywhere with the issue. Thanks

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.

Either way we should have the choice as users to select whether we can use long or short tones because there’s always going to be places out there that cannot register the short tones especially when for example while using tones in when you’re trying to listen to your bank account. That can’t be helped.

I have a post a made about this too. My test involved using bluetooth headsets vs. nonbluetooth, and disbabling wireless calling (T-Mobile) It worked on some headsets but not others with wireless calling enabled (I do not know how audio routing in the iphone works, or if a headset could have a positive effect on wireless calling)

Thank you

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.

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)....

Apple, please fix this! My phone is linked to our community gate entry system and I am unable to buzz in people. Tonight at 11:30 PM this proved to be a huge issue when 911 dispatch could not enter my gate!

Totally unhelpful and totally misses the point. I have an iPhone. You should be able to hold the button down for a longer tone. That's like me saying "The video playback doesn't work on my iPhone" and you saying "Good reason to keep a television set around". Come on.

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.