I want to be able to send SMS from my alarm system. A lot of the sticks online are basically 2G and the UK is getting rid of 2G in 2023 so that’s no good.
Some other sticks like the Huawei E3531 support 3g, but its quite unclear to me if the SMS integrations even use the 3G capability or if they require 2G. If they do, it won’t work for long.
Does anyone have experience with a USB modem integrated in Home Assistant that definitely uses at least 3g (4g also fine)?
I have this one and it’s working 
Actually it looks like 3G might be EOL before 2G in the UK 
But still it looks like both will be available for another decade…
Many countries shut down 3G before 2G/GSM actually. This is because many devices (like smart meters or cars) actually make use of 2G. 
3G is mostly obsolete because it is (in a technical manner) replaced by 4G/4G+/5G. 
2G/GSM on the other hand has native messaging (SMS) and call function 
Sorry to hijack your post but I have a similar question,
I’m looking for a 4 or 5G SMS modem, but it’s unclear to me if a default 4G modem always supports SMS or only data.
I live in the Netherlands and 2G will be phased out somewhere between 2023 and 2025 so using 2G is not an option for me. And afaik 3G will be phased out even sooner.
Also in addition it would be great if this modem can be used as fallback in case internet is down, but that more like a nice to have.
Whilst this seems to be the case all the major providers are turning there’s off very soon The UK 3G network switch-off: what you need to know - Which? News
Your own link tells us the same that I posted already earlier in this thread that 2G will be probably around for another decade in UK while 3G will be shut down already the coming years.
So your statement you made in your first post:
looks like to be not true.
I believe the original question was not about life cycle of mobile phone technologies, but if a modern 4G/5G USB dingle will be able to send SMS using the existing capabilities in Home Assistant, no?
Knowing that 2G will be around for another 10 () years for @adam-thomas-privitar he could just go with 2G now and call it a day a decade. Specially as such a solution is probably one of the cheapest ones and doesn’t depend on HA (directly) being supported (hardware wise) as a esp with esphome and a sim800l module are just enough (or a ready made board like this for example 
Also such a setup could be more robust/resilient than having a dongle to a HA server connected as (with some little logic on the esphome node) the esp can even check if HA is up and send message if it’s down. Even power cycling the HA server (if wanted or requested by SMS) could be easily done from that esphome node if it has a relay attached 
No idea what “exiting capabilities” would be this? Couldn’t find any link to a integration or something in this thread. You got anymore information @EdwardTFN? 
Thanks for the tips. Actually rebooting it via SMS is indeed one of the things I seek here as well. I have plenty of ESP32 spare, so having that as the host controller of the GSM modem makes a lot of sense from redundancy perspective.
Does it have to be a physical device rather than an SMS gateway? Presume resilience is a factor for running locally but does it really offer enough over a managed SMS solution? Weigh up the pros and cons of hosting yourself versus tying into an existing SMS provider.
There are several integrations in HA for using SMS gateways.
Ẃhat would be “enough”? Actually I wonder what a managed (cloud = other peoples computer) solution could do better than a local one?
For the “cloud” stuff working a internet connection needs to be present and the ha server needs to be up, running and be accessible. All of this is not mandatory when you have the ~$10 esphome sms gateway (esp/rp+sim800l) which can be easily extended to even force a restart of your home assistant server 
On the other hand if my HA has cloud/internet access I don’t want to send unencrypted plain text messages (SMS) actually but rather use something with a proper end-to-end encryption like signal for example. 
I’m not suggesting one is better than the other. You mention the need for internet access but on the “self hosted” side you are reliant on having a cellular connection at the very moment you need to send the text - this is why I said weigh up the pros and cons of doing it yourself versus using an out of the box solution.
You do make a good point about SMS as a notification platform - there are much better/safer solutions available, many already integrated, which can make use of Home Assistants Notification framework.
I’m using both. A notification is sent through a SIM800 (not ESP based though) over 2G. If that fails after 5 attempts, the notification is sent through an internet based portal instead as a fallback.
Personally I found 2G networks to be super stable and reliable for this task (more than 4/5G). The fallback was never used outside of testing scenarios.
Unfortunately as some place (like french carribean) the 2g became expensive, you need 4g.
I’m wondering also if i could find a 4g modem that would integrate well with esphome or home assistant 