Hi there ​@HiggsMechanism, sorry to hear this. What are the devices you’re using that should work with us please?

Thanks,

Tyler

They aren’t on your “VoLTE supported” list (and are not showing VoLTE connections) so I don’t expect them to work - the opposite in fact. So I’m surprised that they can do voice and text, but unreliably, which goes against how I think things should work with 3G turned off. Without VoLTE I thought 4G fell back to 3G for voice (and possibly text, the Internet seems confused on that...). 

But to answer your question… my partner and I both have Moto G5+ and I also have a Pinephone.

All three show the above behavior; when *not* accepting voice/text, rebooting often gets the service working again. The “not working” state still shows 4G connection and the only way to tell that there is a problem is to make a call and see if there is a dialing tone. 

Hey there ​@HiggsMechanism, ah I see, thank you for explaining. If the devices don’t have VoLTE, we’d also expect them not to work for calling capabilities as you’ve mentioned, therefore, if for some reason they do sometimes work, then all we can advise if that there’s not much more we can do to make it work fully I’m afraid, as we’d of course expect it to not work. Therefore, being able to make/receive some calls is more than what we’d expect in this instance.

We can only really advise that to be able to make and receive calls properly on our network and our SIM card, you’ll need a supported device with VoLTE enabled.

Thanks,

Tyler

Slightly related, so I’ll mention it here… got a pair of Motorola Moto g56 5G phones (buy one, get one half price offer ATM). These also do not show any indication that VoLTE is in use.

Selecting

settings -> networks and internet -> sims & mobile network -> iD Mobile

does not show any option to enable VoLTE (there is a Voice over WiFi option). however

about phone ->  device details -> sim card status

shows:

mobile voice network type: 4G
ims registration status: registered

With the VoWiFi option enabled the handset-plus-wifi symbol is shown when the GSM signal drops out. Finally, using the magic dialer code *#*#4636#*#* and selecting Phone Info gives the following greyed-out (i.e. unchangeable) options:

volte provisioned <active>
video calling provisioned <inactive>
wifi calling provisioned <active>
eab/presence provisioned <active>

So all indications are that these phones are VoLTE-active even though there is no explicit option selection. Given that the old phones gave the impression of working though, I’m still unsure that this isn’t more of the same and could stop working at any time. VoWiFi is a big winner here though, as indoors reception was very hit-and-miss.

Pretty convinced the Pinephone is correctly working on iD through VoLTE. This is a rather niche Linux-based mobile phone by Pine64, and provides reasonably direct access to the modem. Using this I can see that the response to ‘AT+COPS?’ is ‘+COPS: 0,0,"iD",7’ both outside of a call and when a call is in progress. The key part is the ‘7’ which indicates that the ‘access technology’ is E-UTRAN. So the phone is staying in 4G mode.

This works despite the fact that the default (generic) MBN file.

Investigating the locked-down Motorola Moto G5 Plus will be harder...