Librem 5: Choosing a variant for Gemalto PLS8 modem


#1

The tech specs (https://shop.puri.sm/shop/librem-5/) say librem 5 will use Gemalto PLS8 3G/4G modem.

The PLS8 modem has multiple variants as can be seen at https://www.gemalto.com/brochures-site/download-site/Documents/M2M_PLS8_datasheet.pdf.

I am a Canadian using Freedom Mobile. I would like to use variant PLS8-X for librem 5 as it supports LTE bands 13,17,5,4, and 2. Freedom Mobile supports bands 4, and 7, and will be/already supports band 13. Will it be possible to choose the variant for the modem for a librem 5 phone?

Edit: Seems that baseband modem is swappable: https://www.reddit.com/r/IAmA/comments/87tbfl/todd_weaver_from_purism_doing_a_reddit_ama/dwfh9nb/?st=jfiqa5hg&sh=df3e76c8

The Librem 5 will actually have an m.2 slot for baseband (how cool is that!), so being able to open it up, and swap out the modem, allows for all sorts of additional use cases beyond the core functionality. It also allows us to get pre-certified modems for the regions, so a dual benefit!


#2

The modem featured in Librem 5 is Gemalto’s PLS8. Two variants are used, PLS8-E and PLS8-US.


Librem 5 - LTE Bands support for US
#3

Oh thats a shame. Without UMTS B4 (1700/2100 AWS) i wont be able to get calls or texts

Scratch that, the US modem supports WCDMA BAND4 which seems like UMTS B4.


#4

Are you sure you interpret this properly?

PLS8-US: LTE (   17,5,4,2); 3G (5,4,2); 2G Quad Band
PLS8-X:  LTE (13,17,5,4,2); 3G (5,4,2); 2G Quad Band

So, the difference is only one band. Also, if I understand correctly, SMS could still go via 3G or 2G, either in parallel, or by restricting to 3G.
Nevertheless, would of course be nice to provide PLS8-X on request.
@Richard, I didn’t notice that variant before, as it is only mentioned in the data sheet, not the website. Maybe this variant was added after the decision was made?


#5

SMS should be going (end-to-end encrypted) via the internet, where there is some hope of privacy and security. :slight_smile:


#6

So, the difference is only one band. Also, if I understand correctly, SMS could still go via 3G or 2G, either in parallel, or by restricting to 3G.

Rogers is the only Canadian carrier that has a 2G network since they were GSM based from the beginning. All other Canadian carriers were CDMA, transitioned to HSPA+ AND did not requiring their new “4G” phones to have a CDMA fallback, unlike Verizon. They went from CDMA right to LTE thus needing CDMA for voice calls until they got VoLTE.

@Richard, I didn’t notice that variant before, as it is only mentioned in the data sheet, not the website. Maybe this variant was added after the decision was made?

That I couldn’t say but I don’t know of any major GSM based carriers use that band. Freedom Moble (previously Wind) does not use Band 13, they use Band 66 for LTE and if I remember correctly they’re the first carrier in the world to use it. It’s also listed as AWS-3.

SMS should be going (end-to-end encrypted) via the internet, where there is some hope of privacy and security.

Unfortunately that’s not how SMS works. Unless they’ve got VoLTE, SMS goes through carriers Voice cores and not their Data Core. To encrypt SMS both parties generally need a special app and at that point you might as well just use… Librem Chat!

Haha as smooth as an LTT sponsorship segue.


#7

Yes. Understood.

While my comment was not to be taken too seriously, I would point out that on the iPhone the SMS client makes the decision as to whether to send an SMS via Apple (iMessage) or via the carrier’s SMS service. (The colour of the resulting SMS tells you how the message ending up getting transmitted.) While I am not privy to Apple’s implementation that decision appears to be based on whether both sender and receiver have consented to participate in that (via Settings) and whether both sender and receiver currently have internet (data) connection and more significantly, I would suggest, whether both sender and receiver are using iDevices.

As Apple is “closed” we have no guarantee about the security properties of that service and whether it is better or worse than the carrier’s SMS service, and in what ways.

A similar idea would appear to make even more sense for the librem 5 - but for V1.1, as I dare say that you/they have enough on the plate at the moment.


#8

They will be using Band 13. Wasn’t able to edit my original post
Source: https://www.freedommobile.ca/en-CA/network-and-coverage/coverage

The addition of Band 13 LTE (700MHZ low-band spectrum) to our network means we can strengthen and expand our coverage to even more places.


#9

Yes, Freedom Mobile supports band 13.

I base my statement about not being able to get calls or texts by this reddit discussion specifically about Freedom Mobile and Librem 5: https://www.reddit.com/r/freedommobile/comments/9cncfs/im_buying_an_unusual_phone_will_it_work_with/

Although the reddit post is based on the modems from the dev kits, the same comments about bands still apply

Without UTMS band 4, calls and text won’t work, so at best it’ll be data only.

Beyond that, being only on B4 LTE would give you the most congested LTE experience possible, as most markets only have a small sliver of B4 available.


#10

This not the only difference.
X model doesn’t support voice call. Only E and US variants support phone call.

image


#11

Do you know if it will be possible to have a modem that support the LTE band B28 on the Librem 5?
I live in country Australia, and that specific band is fundamental for any mobile phone here.


#12

By which you mean: in the backwoods / backcountry of Australia?

An area remote from any cities and presumably needing coverage on a lower frequency band?

“I’m not an expert but…” I think that means that you won’t be able to get LTE at all on the PLS8-E, and the PLS8-US would only be marginally better. (Is that something that you have checked?)

Maybe someone from Purism needs to comment on the strategy for international / non-US customers.


#13

It doesn’t mean that I live in the outback, or the desert: outside the big cities (Melbourne, Sydney, Brisbane, etc.) and the small country town (let’s say 20k people?) the main frequency used is B28 - > 700MHz. Without that you are really disadvantaged, because most of the time you probably end on 3G… Even if you live in a city and move often outside, you can have big problems without that bloody band


Librem 5 and Australia
#14

Maybe someone from Purism needs to comment on the strategy for international / non-US customers.


#15

The simplest answer is, this is our first phone, please bear with us. We’re working on some amazing things but it’s hard to do it all at once :wink:

More to the point though is we have to have a baseband (cellular chip that talks to the cell network) that we can seperate from the CPU. This is to allow for a killswitch and that the baseband does not have Direct memory access (DMA). See Kyle’s post about killswitches on the Librem 5 and Nicole’s post about our choice in using a seperated baseband.


#16

Fair enough. Let’s see if you can do with a modem that is OK for our poor bastards down under that don’t live in a big city, otherwise it’s fine, I’ll step back to my purchase and will support the project in a different way.

Thank you for the reply


#17

Wasn’t hassling you to have solved this problem. Was hassling you to communicate your strategy.

For example, it looks as if there is a genuine problem with that geographical location.

Strategy could be

a) delay delivery a bit more for that location, or

b) ship ‘as is’ and send out a replacement module later on, either at your cost or at reasonable cost to the customer - assuming that a replacement baseband module could reasonably be installed by the customer, or

c) bad luck for customer, or

d) withdraw from sale in that location (refunding customers), or

e) something else.

Or some combination of the above.

Yep, I know. Keep doing it.


#18

Our strategy is to develop and release “the World’s First Encrypted, Open Smartphone Ecosystem Giving Users Complete Device Control”.

With freedom you need knowledge. We are giving folks full knowledge about what to expect before they purchase the Librem 5. Not only do we say what bands will be supported, we even release the exact model of basebands we’ll be using, hence allowing this discussion in the first place.

If the phone won’t work in your area, we are sorry that is the case and you do with that info what you will. Remember though that the baseband is connected via an M.2 slot so if you’re able to find one that works in your region, you are free to use it. If you aren’t able to find one then maybe we aren’t either unfortunately.

And I want to re-iterate, this is our first phone. The original iPhone didn’t even get released in Canada and its America’s hat! (More correctly they’re our pants but that is a discussion for another time…)

But since no one seems to have clicked the link above to Nicole’s post about choosing a baseband, I will quote it below:


#19

[We have started] investigating and testing a different modem, in order to evaluate its potential alongside the Gemalto PLS8 one.

Hopefully in the end they offer another modem that fixes some or all of our concerns in here (specific to this thread, UMTS B4 (1700/2100 AWS) and LTE Band 13 and 28)


#20

I don’t suppose someone can post the supported LTE bands in the “different modem”.