Possible End of N900 era on t-mobile US
 

So I just stumble upon a article talking about t-mobiles pending plans.

The article states that t-mobile will be shutting down there 3g/2g network ... as soon as 2021!

So as far as I can tell this means the n900 will no long be able to usable as a cell phone.

Wanted to share this news, and really hope all these linux mobile OS get polished enough for daily use including Maemo-leste.

But also more HW keyboard phone come out, or at least FX comes out with a smaller version of the pro1 ... maybe the pro1/2 :D

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Re: Possible End of N900 era on t-mobile US
 

I was going to post something similar.

T-Mobile will require VoLTE for all phones starting January 2021, AT&T to follow suit in February 2022

In the US, T-Mobile and AT&T are the only national GSM carrier choices (and in the end, US GSM MVNOs generally use T-Mobile or AT&T's network). Unless Sailfish adds VoLTE support (which may not even be enough if this requires carrier cooperation), this would force me to switch to another OS.

Yes, I know, Jolla doesn't support the US market so I should not expect anything. I understand that, but it will still be a little sad for me if/when the day comes where I won't be able to use Sailfish anymore, which has served my needs/interests quite well these past few years.

Edit: Didn't see that this was posted to the N900 forum, but the concern is relevant for multiple devices and OS's running on T-Mo US or AT&T

Re: Possible End of N900 era on t-mobile US
 

This is a no-go! (from both sides)

There are not only Jolla phones out the not supporting but I guess quite a lot of older devices (so-called 'dumb phones' nowadays.
So this topic matches for all devices in (and coming to) the US. What kind of move is this?

And Jolla not yet supporting VoLTE is the other story

Re: Possible End of N900 era on t-mobile US
 

Are we talking about the US of NA in the last three posts?
The articles don't seem to indicate, but I doubt it's global.
In any case, i use neither T-mobile nor AT&T.
This seems like a bad move. There must be millions of devices in the US of NA alone - not only phones, but also in the Internet of Trash - using 3G mobile broadband connections...

Re: Possible End of N900 era on t-mobile US
 

Would this not be the same fate for the n9/n950?

Re: Possible End of N900 era on t-mobile US
 

This is limited to a few areas. Mostly as CDMA type systems used the same frequency as GSM in some areas. So alternative GSM frequencies were used which are now needed for 5G. USA, Australia and Singapore to my knowledge, there might be a few more. Otherwise the most likely development for the rest of the world is 3G will be retired, leaving 2G networks for older IoT devices.

Re: Possible End of N900 era on t-mobile US
 

2g and 3g are for data. Voice is on GSM. Even with 4g voice is still on GSM.

Re: Possible End of N900 era on t-mobile US
 

When T-Mobile ends 2g/3g support in the US, the N9/N950 will no longer be supported. AT&T's 3g bands never properly supported the N9 everywhere, and AT&T has phased out its 2g. T-Mo has kept 2g up and running this long to support stuff that was the internet of things before there was an internet of things. Burglar alarm backups, lo-jack, and even connected scales, e.g. But now there's a low-power, low data rate 5g service that can finally replace these aging devices on aging networks -- and the N9 is a casualty.

Re: Possible End of N900 era on t-mobile US
 

Important.
Many people, even on technical forums, are confused by and/or unaware of this.

(and yes, there's some technology that can send high-quality audio for calls ovwer 4G, but I'm sure that's optional and calls are still possible without any data connection at all).

Re: Possible End of N900 era on t-mobile US
 

Well it would be useful info if t-mobile would actually indicate if this is actually the case. Since for me a phone without data is still useful, since I can do hotspots or hop on wifi when needed.

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Re: Possible End of N900 era on t-mobile US
 

Yes, it is possible to make phone calls using LTE network only. This technology is called VoLTE.
It indeed uses data transfer under the hood but the data is being routed differently than "normal" data transfer and therefore works without a need to have cellular data connection enabled. And this is the technology which will be somehow "required" in T-Mobile US and it is being integrated in many LTE networks all around the world.
An equivalent for 5G is called VoNR (Voice on New Radio) or Vo5G.

It is called HD Voice. And as far as I know it can be used even on old 2G network but US operators lauched it alongside with LTE. Perhaps so that the user can "hear the LTE improvement". ;)


P.S. There is also LTE Broadcast (also called eMBMS, for 4G) and 5G Broadcast (also called FeMBMS) for transmitting (emitting, multicasting) data (f.e. TV, radio) using 4G or 5G with possibility to receive data without any additional charge and even requiring the SIM card. But, unfortunately, it is not popular - there were just few public tests of these technologies.

Re: Possible End of N900 era on t-mobile US
 

I was refering to the opposite: It is possible to make phone calls without any data connection, i.e. without LTE, without 2/3/4/5G.

People seem to have lost that knowledge; I'll say it just one more time:
There's technology for mobile calls and SMS, usually called GSM, and then there's all the rest, call it mobile broadband, internet, data, whatever.
Every smart phone ever built (*) has had (and still has) at least those two technologies side by side.

(*) assuming part of the definition of "smartphone" is "internet capable". And if someone brings up WAP now I'm going to scream...

Re: Possible End of N900 era on t-mobile US
 

The "traditional" GSM voice call which is called circuit switched connection to differentiate from the packed switched connection of the "data call" still needs the 2G or 3G cell to work.
If an operator runs down the 2G/3G network and allocates the cell sites to LTE or 5G then you lost this capability.

Re: Possible End of N900 era on t-mobile US
 

Slightly OT but what about e.g. all those emergancy systems used in elevators that have been installed over the last 20+ years?
Isn't it likely the providers just stop selling the feature to public but still offer it silently to b2b customers?
Or will we see elevators get upgraded all over the US?

Re: Possible End of N900 era on t-mobile US
 

I might have to go to Alaska for some work, not sure though.
I do not look forward to having to deal with the doing-our-own-thing tech/contractual mess that is mobile service in the US/Canada.
I think even Japan has now gotten onto the global mobile telephony standard and freqs.
Will the Pinephone work there?

Re: Possible End of N900 era on t-mobile US
 

You know this discussion reminds me that as much as some don't like Purism. If they had a phone that worked well (meaning you don't have to think about power usage and heat issues), then their approach of separating the modern (M.2 slot for a baseband module) onto a daughter board makes a lot of sense ... as long as you can find or they sell a replacement.

Imagine keep the device you want just update the components. Fairphone does this to some extent, sadly I don't think the cpu/modem though.

x

Re: Possible End of N900 era on t-mobile US
 

How can it then be that I have a "GSM only" phone?

Re: Possible End of N900 era on t-mobile US
 

I know that some of the remote areas of Alaska are using microwave links for phone service in the small towns.
And going to such a remote area, you might need a satellite phone.
Yes there will be cell coverage in the large cities such as Fairbanks.

Re: Possible End of N900 era on t-mobile US
 

Much of the western US used to be linked by mountain top microwave horn emplacements. I think most are replaced by fiber now.
When you get high enough even the up to 45 degree LEO sats like Globalstar get hard to access, forget geostationary orbit inmarsat to low on the useful horizon and I guess only Iridium with its LEO polar coverage comes into it's prime. IDK most of the time I would be in Anchorage but yea if I have to go north I guess it is wireline, QRP HF amateur radio or Iridium along with all of the offline data I can stuff into flash drives.

I noticed inmarsat recently tossed up data package on three Molinya orbit birds to give virtual geostationary coverage to the norther polar area. No idea how mobile the equipment is, probably is a steered dish antenna or a phased array pizza box like starlink.
https://paxex.aero/2019/07/inmarsat-gx-arctic-coverage/
that has to be some wicked doppler.

Re: Possible End of N900 era on t-mobile US
 

What is it you don't understand about it?

Re: Possible End of N900 era on t-mobile US
 

Some interesting read here:
https://forum.sailfishos.org/t/volte...fishos/1093/24

Re: Possible End of N900 era on t-mobile US
 

Very interesting. s1p might be the way forward for me, as I would rather continue using Sailfish. That would also depend on whether a data-only SIM card would continue to work.

Re: Possible End of N900 era on t-mobile US
 

Well, there's my cheapo Nokia 130 (2017) which is GSM only - I understand this to mean that it simply does not have the hardware to connet to 2,3,4,5G networks.
How can it then be that "The traditional GSM voice call ... still needs the 2G or 3G cell to work", as you wrote?
Does the GSM network itself rely on 2/3G, even if the phones using it don't?

I had a look at what peterleinchen linked but I still don't get it.

Re: Possible End of N900 era on t-mobile US
 

"GSM" means "2G". Period.

GSM refers to the modulation and timeslot structure that is used to transmit data over radio waves between your handset and the base station. (GSMK modulation, 8 timeslots)

The data that is transmitted can be any of a number of packet data, including digitized voice packets, control messages, SMS messages, IP, etc...

It is entirely possible that the baseband in your handset can only handle and use digitized voice and SMS, however those are just a subset of the specification and the base station sure can handle everything.

Re: Possible End of N900 era on t-mobile US
 

Devices that support LTE but do not support VoLTE (making phone calls though LTE) in a specific operator's network just before a phone call do connect to 2G or 3G network in order to make a call. It is being called Circuit-Switch Fallback (CSFB). After that they (should) switch back to the LTE network connection.
Devices which support both LTE and VoLTE in a specific operator's network during a phone call use LTE network to make a call.

Re: Possible End of N900 era on t-mobile US
 

Oh! I really did not know. Thanks for taking the time to explain it. I would've stumbled over this for years to come...

Re: Possible End of N900 era on t-mobile US
 

I had a problem for a while whereby, after I switched to Jolla (which required cutting my SIM card), I could not switch back to my N900. The phone asked for the SIM card PIN but that's it, no mobile signal after that.

To cut it short, the problem was that I somehow switched my N900 to "2G only", which rendered the phone incapable to even register with my mobile network (3 UK). As the name suggests, the network does not even have the 2G infrastructure, it joined the scene after the introduction of 3G. Switching the phone to "2/3G" or "3G only" saved the day.

How would you explain that? The phone needs 3G at least for the registration, but then uses 2G for making calls? Or are the calls somehow routed through 3G after all?

Re: Possible End of N900 era on t-mobile US
 

I do not understand your question?
juiceme explaine bit here.

If your provider does not support 2G (GSM) then you need another technology. In case of yours it is 3G (UMTS) which both support voice calls with CS. Up from 4G (LTE) you need a VoLTE capable phone.

Re: Possible End of N900 era on t-mobile US
 

Easy to explain, also 3G (which actually is called WCDMA UMTS but some people prefer 3G, maybe they think it is shorter thing to to say...?) provides wireless packet connectivity of many types just like GSM, plus a handful of oter new protocols.

So when you make a CS voice call with your 3G-only network, it handles the packet flow over the WCDMA air interface. Also you have the advantage of having simultaneous PS access which people notice for example when surfing with the phone while having a voice call.

Re: Possible End of N900 era on t-mobile US
 

And further on with the same topic now as I got into speed;

4G networks (which actually are called UMTS Long Term Evolution, or LTE for short) are structured a bit differently from the earlier GSM and 3G networks. On the backhaul side they do not have ATM any longer but are connected to the core with IP routers only.

This is the reason there is no CS call possibility in LTE, and your only option for a voice call is either drop the connection to either 2G or 3G or use VoLTE which is an end-to-end IP based call.

The same thing goes with 5G, just like LTE it has IP only backhaul and core and similarily only supports IP calls.

Re: Possible End of N900 era on t-mobile US
 

Nw as I came to think of, it might indeed be that there are some people who do not know the internals of cellular networks.

It might be that I am glossing over some bits due to the very usual mistake that people make, assuming that other people already have the basic knowledge because everyone around me knows these things.

So, here is really quick introduction to the different ETSI-GSM generations;

2G, original GSM
First wholly digital cellular radio system. Originally designed for voice only, later enhanced by services like SMS messaging and IP calls.
Air interface is based on a slow frequency hopping scheme, with TDMA interleaving with 8 timeslots.
Much of the network intelligence resides in the core side, BSC and MSC elements. BTS is fairly dumb device which only really connects the air interface to T1/E1 SDH links. The backhaul is SDH and ATM.
The reason why it is not practical to have simultaneous CS and PS calls is primarily the limited bandwith of the air interface and secondarily the routing of the backhaul T1/E1 to specific network element that is used to route the PS call to internet.

2.5G, enhanced "Edge" GSM
This basically adds possibility of allocating more than one timeslot per UE, so that downlink data rates can be doubled or quadrubled.
Of course this also limits the number of UE's in the cell accordingly.

3G, WCDMA UMTS
3G is a logical continuation of the ETSI spec and can coexist with 2G well but it completely overhauls both air interface and backhaul.
Air interface is based on fast frequency hopping by code spreading. Signalling is very complex and there are huge amount of different options and tunables.
BTS is more intelligent than on GSM, transferring some BSC functions to the edge. Backhaul is ATM and the rich signalling allows simultaneous use of several logical channels which means for example CS and PS calls.

3.5G, HSDPA and HSUPA extensions
Small enhancements which are basically just software tweaks in signalling to group logical channels so that data rates can be increased. HSDPA (=High Speed Downlink Packet Access) is the more common 3,5G technology, HSUPA which is the same thing for uplink direction is a bit rarer feature.

4G, LTE (Long Term Evolution)
This again revamps both air interface and backhaul, where CDMA is now dropped for ODFMA and ATM is finally put to rest and IP goes directly down to BTS.
Signalling is actually simpler than on 3G which was really an elephant on that respect, still more intelligence is distributed towards the edge and the BTS is now handling quite lot of things by itself.
Because SDH/ATM has been dropped from the backhaul CS calls are no longer possible and indeed thare were emerging operators that had no telco legacy and implemented VoLTE-only networks.

5G
This is really more or less an umbrella standard covering a wide range of modulation and spectrum allocation technologies for different use cases. (everything between very low-power/low-bandwith IoT gadgets to super-low latency factory automation and autonomous vehicle control and super-high bandwith for media terminals) Like 4G this is also All-IP network and again more intelligaence is pushed toward the edge, so BTS sites will have cloud-computing resources for some nice new functionalities and services.

To recap; all evolution of the ETSI-GSM networks has been to the direction of pushing more and more functionality and intelligence from the core towards the network edge. Because the air interface is the "last mile", everything can be done faster when the processing is nearest to UE and signalling is done in the BTS to minimize the loops done via the backhaul.

Re: Possible End of N900 era on t-mobile US
 

I understand that the network is capable of doing that. But it also means that the phone must be capable of doing that too, right? Which is kinda incompatible with this claim.

You cannot have it both ways. Either "voice is always on GSM" or "voice is not always on GSM" :confused:

Sorry to be a nuisance, but I'm still confused :(

Re: Possible End of N900 era on t-mobile US
 

In case anyone is wondering why the history starts from 2G, the first generation mobile phones were anaologue. With no scrambling or encryption. You could listen to at least one side of the conversation (because different frequencies were used for up- and downlink) if you had a radio receiver that could be tuned to the relevant frequency. Don't ask me how I know ;)

Re: Possible End of N900 era on t-mobile US
 

And some call even older technologies the 0G (zero G). :)

Re: Possible End of N900 era on t-mobile US
 

Well, think of it this way.

With all ETSI-GSM family networks, voice call is always "digital", however there are two ways to set up the voice call.

• 1.) The "traditional" digital telephony way, which is pretty much adaptarion from digital switching of the old-style non-mobile land telephony, usually called CS (Circuit Switched) call. This relies on SDH/ATM backbone and establishes a virtual switched circuit between the UE's. (This means there is a dedicated channel and timeslot for the call which is reserved for the duration of the call)
• 2.) The newer Packet Switched (PS) call which is just digitized voice call carried over IP/UDP packet stream, no preallocated routes needed.

The 2G and 3G networks have SDH/ATM backhaul and can establish CS calls, 4G and 5G cannot do this.

The 3G, 4G and 5G networks have IP backhaul and can establish PS calls. (and actually at least theoretically also 2G could do that because it could use VoIP over data connection altough I don't think that has ever been released in a public network)

The reason 3G is such a beast is because it has dual backhaul and also the additional burden of managing the power control over multiple cells which is required by the CDMA modulation scheme... compared to that 4G signalling is a walk in the park!

5G again gets a whole load of new stuff which ramps up the complexity (ultra-short feedback loops over air interface, adaptive antenna-array control, management of several modulation techniques simultaneously, etc...)

Re: Possible End of N900 era on t-mobile US
 

Thanks, juiceme, but unfortunately, instead of simplifying it for me, you complicated it even more. Maybe we are talking about different things. All this time I was talking about the communication between the handset and the nearest cell tower. I understood the "voice is always on GSM" claim in that context and that context alone. Maybe I was wrong and needed to take a more holistic approach.

Re: Possible End of N900 era on t-mobile US
 

Indeed we could be talking past each other, happens to me all the time! :D

I was mainly pointing out the differences in backhaul, which in reality are the more important things, air interface is just air interface :)

So, when concentrating on the air interface, between the UE and BTS, there is not really that much difference between whether the call is CS or PS. All the difference is in signalling; how to establish the routing of the data in backhaul, what codec, channel configuration and data rate to use, etc...

So the question "is CS call always GSM?" is a bit misleading; "GSM" is not a very specific term really. :eek:

Re: Possible End of N900 era on t-mobile US
 

Some news regarding Jolla and VoLTE, found in, of all places, the latest Ubuntu Touch Q&A summary:

Obviously this information is Ubuntu Touch and PinePhone-centric, but it is interesting that Jolla got a mention and that they all meet on these issues.

Re: Possible End of N900 era on t-mobile US
 

Did a imei test recently and t-mobile says what we already figured out.

Here are the screen grabs of the results from https://www.t-mobile.com/resources/bring-your-own-phone

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Re: Possible End of N900 era on t-mobile US
 

But nice is that even your phone is definitely not supported T-Mobile offers you as next step to buy a SIM!? :rolleyes: