No one is able to say how many business people, tourists and family visitors will be affected: just that technology changes mean people going from Europe and elsewhere to the US will no longer be able to make any voice calls – not just to 9‑1‑1, the US emergency services number, but to any fixed or mobile number.
Jérôme Hardouin, technical director in Orange’s wholesale business, says the issue has been “triggered by the US”, after first AT&T and then T-Mobile US decided to shut down its legacy networks. “When AT&T made its announcement, we started taking action.” That meant Orange accelerated work on providing alternatives.
A Vodafone group-level executive told Capacity that, since AT&T started closing down its 2G and 3G services a few weeks ago, “Vodafone customers travelling to the US are still able to make voice calls via T-Mobile US.”
However, this official missed the fact that T-Mobile US is also shutting down its 3G network, though it is currently planning to keep 2G alive.
Just to demonstrate the extent of confusion in the industry, another Vodafone executive said: “From 1 July, T-Mobile will be switching their 3G network off in the US, resulting in some customers experiencing service issues when trying to send texts, make calls or use data.”
It’s clear that foreigners visiting the US will have to develop skills in changing their phone settings. As an official of one European operator said, “customers who have a 4G capable handset will have access to the AT&T 4G network for data only, and the T-Mobile 2G network for voice ”.
That assertion implies customers will have some technical skill in switching from one network to another when they are in a collision on the highway, smell fire in their Airbnb or find themselves having a miscarriage or a heart attack.
Ironically, AT&T has the US government contract to operate FirstNet (pictured), the country’s emergency services network that provides connectivity to police and other first-responder organisations. But, extraordinarily, there is no legal requirement for US operators to offer emergency services to foreign visitors, a European regulator confirmed to Capacity.
The US regulator, the Federal Communications Commission (FCC), requires US-licensed operators to provide their customers with high-quality access to 9‑1‑1. As well as connecting the call, they must supply information about the location of the phone making the emergency call, as well as the phone number.
But that requirement doesn’t extend to foreign mobile roamers in the US. “It’s left to the market,” an executive at one European regulator told Capacity, on condition of anonymity.
The situation is likely to get worse, as other operators around the world shut off their 2G and 3G networks to make more spectrum available for 4G and new 5G services. The original GSM mobile technologies – 2G from the 1990s and 3G from the early 2000s – were used as the common denominator for global roaming. But they now have limited life ahead of them, not just in the US.
UK operators, for example, will start to close their legacy networks in 2023-24, shutting them all by 2033, as agreed with the UK government.
Robustel, a Chinese supplier of internet-of-things (IoT) systems, has a long list of what’s closing when across the world. IoT services often use 2G or 3G for connections.
These two earlier generations of mobile used a technique called circuit-switching to connect callers, using wireless links in place of the copper wire that the telephone industry has used since the days of Alexander Graham Bell.
But 4G, the fourth generation of mobile – also known as long-term evolution (LTE) – uses different technology, a data connection called voice over LTE (VoLTE). When 4G was first introduced, VoLTE wasn’t ready, and 4G-capable phones “fell back” to a 3G connection for voice calls.
Rudolf van der Berg, at Stratix Consulting in the Netherlands, told Capacity: “Circuit-switched fallback is your friend. If that doesn’t work, you’re doomed.” He told Capacity: “It is deeper and dirtier than I ever imagined. VoLTE emergency is standardised, but doesn’t work everywhere, I would say.”
He addressed the European Emergency Number Association (EENA) in Marseille in April, telling them that Europe’s 112 standardised emergency number “is a massive success”, but in the US you might not be able to call the equivalent, 9‑1‑1. He said that AT&T is telling people arriving in the US: “Our 4G implementation doesn’t work with your phone.”
In his presentation, available online, he contrasts two apparently identical phones from one maker. One can do VoLTE roaming but the other can’t.
Orange’s Hardouin said: “Not every [4G] device is VoLTE compatible, but some are not suitable for roaming.”
Once T-Mobile US starts to turn off its legacy service in July, “Europeans will be stuck”, said van der Berg at Stratix.
Capacity contacted Deutsche Telekom, which is the dominant shareholder in T-Mobile US and also owns Deutsche Telekom Global Services, a unit that provides roaming, messaging and other international services between network operators. It did not reply.
Incidentally, Verizon’s 2G and 3G networks use a different technology to global GSM-based standards for 2G and 3G, so foreigners in the US could never roam onto Verizon. It plans to close its 3G legacy network at the end of 2022, for the same reason as AT&T and T-Mobile US – to free spectrum for 4G and 5G.
At Orange, Hardouin said the group has agreed VoLTE roaming with AT&T for its operations in France, Belgium and Slovakia, and is steadily working through the others. “And we’re starting with T-Mobile.”
Freddie McBride, director of policy and regulatory affairs at the EENA, told Capacity: “The idea that anyone would be refused a voice service because of technical issues just doesn’t wash.”
He noted that travellers have been used to international voice roaming for two decades, switching on their phones on arrival at airports and making calls immediately. “Why should it not work now?” When he saw a text message from AT&T saying calls were no longer possible, “my jaw hit the floor”.
A senior technology executive of one Europe-based operator confirmed the changes to Capacity, speaking on condition of anonymity.
“For several years, a large majority of operators have launched and fine-tuned their VoLTE service while keeping their circuit-switched (CS) voice service, which was still used for roaming. Roaming agreements were built for the CS voice service, based in minutes of connection,” said this person.
“New roaming agreements are needed for VoLTE because the voice connection is a now a data connection, even if the operators still charge it in minutes.”
But many 4G phones outside the US don’t have VoLTE, and they are designed to fall back to 3G for voice calls. This makes them suitable for roaming in most places where 2G and 3G services still exist. But with no 2G or 3G, this won’t work.
Orange believes that more than 50% of the phones on its network are VoLTE-compatible – though the percentage is closer to 80% among users who travel internationally. But that still leaves one in five or even more likely to land in countries where their phone won’t work to call 9‑1‑1.
To make matters even more confusing, having a VoLTE phone isn’t enough. A technology executive at a significant global operator said, “new roaming agreements” are needed between a person’s home operator and the one connecting them in the US before they can make voice calls – though, in theory, emergency calls are accepted even without agreements.
Three conditions are required for VoLTE roaming to work, this source told us.
A 4G phone must have VoLTE service enabled;
The phone needs to have VoLTE roaming enabled (some automatically disable VoLTE and revert to circuit-switched voice while roaming); and
The home operator and the visited operator must have a VoLTE roaming agreement.
In addition, phones often need to be approved for use on a customer’s home network. A phone, even a high-quality phone, bought from a vendor such as Amazon and fitted with a SIM card, won’t necessarily work, a European regulator told Capacity.
BICS, the global services arm of Belgian operator Proximus, frankly admitted: “This is of course less than ideal, but the situation is temporary. It will be resolved when VoLTE roaming agreements are signed between AT&T and non-domestic roaming carriers. This can happen really quite quickly if the carriers partner with global roaming providers.”
But we’re not there yet. McBride at the EENA said the consequence might be “someone dies”.
The business reason for these huge technological changes is that operators have been facing the challenges of keeping four separate networks in side-by-side operation – 2G, 3G, 4G and 5G – with the earliest two generations using lots of spectrum but generating little revenue from global roaming and some IoT services.
AT&T was first in the US to announce the phased closure of 2G and 3G, a switch-off that began on 22 February 2022 – or, memorably, 22-02-2022; or 2/22/2022 if you’re American.
Capacity staff and others attending International Telecoms Week (ITW) just outside Washington DC reported issues a few weeks later, in May, but others – including senior telecoms executives – had reported similar experiences earlier than that.
What many Capacity staff saw on landing in the US, for many for the first time since 2019, was a text message from AT&T saying: “Welcome, you are roaming on AT&T. Due to network technology compatibility, traditional voice calls will not work. Please use data, SMS, and app-based calling.”
AT&T thus confessed it was throwing away the chance of earning roaming voice revenue and was telling people to use a data service – though it didn’t recommend, or even list, any data-based voice services. It assumed people would know what “app-based calling” meant – and assumed people would be able to log on to a local Wifi signal so they could download an app that allowed them, in the absence of 4G roaming, to make calls.
With AT&T shutting down 2G and 3G it has had to ensure that it can deliver 9‑1‑1 calls made over VoLTE from its customers to the right public-safety answering point (PSAP), the incoming call centre that directs emergency calls to the right service.
In the US, PSAPs are run locally, so this is a complex, location-based business. In the US, the National Emergency Number Association (NENA) says incoming 9‑1‑1 calls have to be directed to one of 8,883 possible answering points, made up of 5,748 PSAPs plus 3,135 counties, where local officials handle calls.
By contrast, in the UK there is a nationwide service to handle all calls to 999, the UK emergency number, introduced 85 years ago, or to 112, the pan-European number. A human operator uses automatically provided location data to redirect the caller to the right police, fire or ambulance service, or to the right coastguard.
Roaming visitors to the US who dial 9‑1‑1 on their mobiles also need to be redirected to the right place. But there’s a quirk about VoLTE. “Your VoLTE session will go back to your home operator,” said Nick Wennekers, VP of product management at Tomia, a software company that specialises in roaming technology. “A VoLTE call is a data call,” added Wennekers, who was also unable to make standard voice calls from Capacity’s ITW event in May. He said that AT&T is aware of the issue and is looking for ways to fix it. However, it appears that 9‑1‑1 calls over VoLTE are routed to a PSAP, though even people experienced in roaming are confused.
AT&T misunderstood the reason for Capacity’s request for information on this issue, treating it a request for personal help. “What device were you using when you were unable to make calls on our network?” said a senior executive in corporate communications, even though Capacity had asked about the general, industry-wide issue.
At Tomia, Wennekers said that AT&T has adopted a solution from Syniverse. But Syniverse did not respond to requests from Capacity that began in mid-May.
Dean Bubley, an industry analyst and strategy advisor, said of the whole 9‑1‑1 roaming issue: “The emergency service is the thing that will make a difference, especially if lawyers get involved.” He likened it to the famous butterfly effect, where “small events end up having large consequences”. And then “a whole bunch of stuff starts unravelling”.
Bubley said “every telecoms lawyer in the US” will be looking at this issue “and talking to their mates in liability law”. He also said he expects providers of travel insurance insisting their clients visiting the US ensure they install app-based calling on their phones before leaving home.
“That means predominantly Skype,” he noted. The Microsoft-owned app once warned customers that it could not be used for emergency calling. It still does outside the US. However, in February 2022 – coincidentally just as AT&T was starting its great 2G and 3G switch-off – Skype started supporting calls in the US to 9‑1‑1.
It recommends users to enable 9‑1‑1 emergency location sharing “to permit Skype to automatically capture and share your location with emergency operators”.
Bubley offers a possible solution to the dilemma. For most places, “a thin layer of GSM”. That is, a 2G service – “which might be government run”, he said – to offer roaming voice and 2G-based IoT services, perhaps until a global conversion to 4G and then 5G is complete. “You might only need 5MHz of bandwidth as a lowest common denominator”, he added.
McBride at EENA agreed, suggesting a 2G legacy network, at least in Europe, as “a network of last resort”. But “the regulators won’t like it,” he said.
Is anyone warning customers of these issues. Hardouin said Orange sent text messages to customers at the end of 2021 and again in February as AT&T was beginning its closure, especially to those who had bought an international roaming pass. But, he admitted, “the communications need to be global”, in other words, to people who are not frequent flyers but are using the end of Covid travel restrictions to visit the US.
Are airlines or travel agents warning customers? Capacity didn’t get any warnings from our parent company’s travel agency, even though the company subscribes to a risk-warning service that sends alerts about traffic disruption in places staff might be visiting.
Capacity put a number of questions on this whole complex issue to the FCC. It did not reply.
