Technological changes, mainly from the US airline AT&T, mean that when travelers turn on their phones after landing, they will receive a message warning them that “traditional voice calls will not work”.
The lack of traditional voice chat means that unprepared visitors to the United States will remain unable to call landline or cell phone numbers – such as their hotels, car rental companies, or perhaps 911 emergency services – or even friends and relatives in the United States or at home. . They will also not be able to receive calls.
AT&T – once part of the powerful Bell System – advises them on texting to use “data, SMS and app-based calling”, although international travelers have often routinely turned off data roaming due to high costs.
That means calling with apps like WhatsApp from Meta or Facebook Messenger from the same company. But they can only be used by people who have installed these apps on their mobile phones – and are willing to pay the cost of data roaming.
And travelers should set up those services in advance, without waiting for a taxi or booking a rental car at a U.S. airport.
But neither Facebook Messenger nor WhatsApp can be used to call regular landlines or even mobile customers who have not installed the apps on their phone.
Skype is one of the few applications that can be used to make regular phone calls, but only by users who pay an upfront fee to Microsoft, which owns the service.
School holidays in the UK are starting this spring, and German holidays are starting next week, which means many families who land at US airports will be surprised by AT & T’s text messages.
Customers from a number of UK-based operators, including EE from BT, Virgin Media O2 and Three, have reported that they cannot make or receive normal calls while in the US.
This morning Vodafone UK has not yet responded to a survey sent by Capacity last wednesday.
A spokesman for Tri UK said: “It seems that the problem you are experiencing could be something to do with the disconnection of VoLTE and 3G in the US.”
This person has noticed that some devices may not be compatible, and some device manufacturers “have been reluctant to update their customers on this”.
Behind the changes is AT & T’s decision to withdraw its 2G and 3G networks – the main services that have been used for international roaming for the past 20 years – so that it can reuse the frequencies for more modern 4G and 5G technology.
Some customers find that incoming calls are diverted without explanation to voicemail, but then cannot always access their voicemail services. Visitors to the United States who try to make outgoing calls, whether to U.S. or international numbers, are removed within a second or two without explanation.
Even AT&T and the wider industry are confused about the impact of the changes.
An official AT&T spokesman suggested on Friday that Capacity that a relatively new technology called Voice over LTE (VoLTE) will solve the problem, even though many phones do not have VoLTE, which enables digital voice calling over 4G networks.
And for those with more modern phones, VoLTE roaming needs specific agreements between the person’s home carrier in Europe and the one providing the service in the United States.
“We recently launched a VoLTE gateway with your carrier,” AT&T said Capacity a writer who has experienced just this problem in some U.S. cities, being unable to make or receive normal voice calls in Boston, Philadelphia, or Washington, either by regular cell phone signals or by Wifi in hotels and apartments.
“The message you received on arrival was sent incorrectly and is only intended for carriers who do not have approved roaming capabilities with us,” AT&T said.
Yet despite this apparent agreement, this Capacity a writer, a client of Three, was unable to make calls via AT&T. Capacity did not attempt to make test calls to the 911 emergency service while in the United States, but there is no reason to think they could be an exception. Probably 911 calls are also blocked. In a recent change, Skype now allows users to call 911 in the United States.
Three UK said: “In the US, Three has seen its roaming partners shut down their 2G and 3G networks, meaning all voice services will be inaccessible to customers. Ultimately, Tri has no control over its partners’ infrastructure plans, but aims to have a variety of partners. with access to different spectra in each destination. “
An official from the GSMA, the mobile phone industry’s trade association, said in an e-mail: your account was not VoLTE-enabled by your provider; or you have a phone that does not support VoLTE services. “
Most of these suggestions were wrong, as the mobile phone regularly makes VoLTE calls in the UK and also did so in France.
“All of these issues would mean that voice calling would not be supported on a 4G VoLTE network – but data services would still be available,” the GSMA said.
“In addition, there may not be a 4G VoLTE roaming agreement between the US operator and your provider,” the GSMA added – something contradicted by AT&T, which said there was a 4G VoLTE roaming agreement with Three UK.
Three UK advised: “If you are connected to a 4G data service but are unable to make or receive calls or texts, you probably have a 4G capable device, but the software has not yet been released, or you do not have it. Updated the latest software version to enable this that. “
Dan Warren, now director of advanced network research at Samsung’s UK labs, was one of the people intimately connected with the VoLTE specification a decade ago at the GSMA, where he was senior director of technology. He confirmed that VoLTE was most likely the issue.
He also received an AT&T warning message when he landed in Boston two weeks ago. “I had all the same thoughts but also had a slightly more urgent need because I didn’t have cash but needed to call my hotel to call a shuttle bus,” Warren said. “I guess it’s related to VoLTE.”
Capacity also spoke with others left unexpectedly able to make calls while visiting the United States, including the CEO of a major international airline.
Capacity spoke with Chris Lennartz, VP of mobile services product management at iBasis, one of the leading companies the mobile industry uses to direct roaming calls and messages. He also experienced the problem as the world opens up post-Kovid: “We had people coming to the United States in February,” he said. They experienced similar problems.
Operators are trying to simplify their network operations, he said, which means not operating 2G, 3G, 4G and 5G in parallel. They mainly introduced 2G in the 1990s and 3G a decade later, in the early 2000s.
“AT&T’s 2G and 3G shutdown began in February,” he noted. “In some places it still works.”
Of the two other mobile networks, Verizon also disables 2G and 3G, but those networks were never used for international roaming because Verizon then used a standard that was incompatible with most overseas networks. Verizon did not even join the GSMA until 2010, when it decided to adhere to global mobile standards and began building 4G.
Deutsche Telekom-owned T-Mobile US “turns off 3G in October, but not 2G,” Lennartz said. Technically savvy visitors might be able to force their cell phones to roam on T-Mobile in the U.S., he suggested. A visitor’s home operator may refuse to authorize as a connection, he warned.
A Three UK spokesperson said customers left unable to make calls should “manually search for the other provider (T-Mobile) to connect to all 3G services”.
However, at iBasis, Lennartz said that a non-US phone will usually start by finding a 4G data connection at AT&T, but will later fail to find a 2G or 3G service for voice on the same network.
iBasis is looking for a solution, Lennartz said. “With a little witchcraft we could make it work.”
However, because international VoLTE calls – even when they are running – are all database-based, and tunnel through the global mobile system, there is no incoming revenue for calls. Operators are “missing out on a lot of revenue,” he said: the implication is that there is no financial incentive for operators to make a global vagrant VoLTE work.
“It’s a very precarious situation, but AT&T is doing everything they can,” Lennartz said.
The GSMA said: “The decline of 3G networks is not as advanced in Europe as it is in the United States, which in turn means that VoLTE is not as widely used for voice services. It should be noted that this is not an executive business decision based on the priorities for home customers.
But it is a decision that may surprise thousands of international visitors to the United States – and the coming days will be the first time most of them will find out.