Chosing the right modem PLS8 vs BM818


#1

Since the hardware update everyone of us faces the decision of the modem. This topic aims to help everyone with that decision.

To choose between the options
Option 1: Gemalto PLS8 3G/4G modem w/ single sim on replaceable M.2 card
-> In fact there are two options here with PLS8-E and PLS8-US - right?
Option 2: Broadmobi BM818 (made in China)

It would help to know on what base to choose (to enable us as customers to choose)

So I would base my decision upon:

  • Does it work in my region / does it work to where I travel?
  • Which might have the lower SAR / DAS?
  • Which has the higher speed
  • Where will purism invest more likely effort to free the blobs?
  • Something else (there is the made in china - I don’t know why this is important)

I know that there is a table which shows the different bands for the PLS8-E and US - I think this would need to be extended for the BM818
https://puri.sm/faq/supported-networks/

A related topic (which I didn’t want to use for this, as this topic here should only be used to elaborate the differences between the 3? options)


Librem 5 - LTE Bands support for US
#2

The Broadmobi devices all support more bands and will thus work in more places.

Both are largely identical, depending on the used band. Maximum transmission power depends on the band you’re using at the time, but they are in the same ballpark for all devices.
The characteristic is more dependent on the antenna location an design and this will necessarily be identical for both variants.

The Broadmobi devices are Cat4 devices and thus generally faster than the Cat3 Gemalto.

Freeing either of those devices is highly unlikely and there will be no blobs (which by definition are binary components loaded by the host system).


#3

Are the ranges supported by Broadmobi BM818 a proper superset of those supported by PLS8-E? Or are they disjoint? Having more bands does not mean much if the most important bands are gone.

It would be handy to have there indeed.

Either way nice to get an extra option.


#4

Still I do not know how to choose. The specs say that Gemalto is on M2 replaceable card. But it does not say the same for broadmobi. What does this imply? Is Gemalto on M2 a better choice? Is broadmobi a faster choice? Do both Gemalto-E and broadmobi work in Europe? I think we will need help and more information on this in order to decide.


#5

Yes, Purism should use their research to inform their customers.


#6

As stated in a different topic, I think the wording needs to be improved:

I’m pretty sure we’ll get more information about how to choose an alternative modem - it seems to me that they postponed the release of the specs just to be sure the Broadmobi will also work - because only a few weeks ago, that was not clear (Nicole mentioned working on an alternative modem choice).
So, give them some time to fill in the gaps.


#7

Is the Gemalto PLS8 not made in China?

Edit:

This seems to be referring to the Gemalto PLS8.


#8

Right, the Gemalto modem is designed and made in Germany, it will be placed on an M.2 card in the USA.

Cheers
nicole


#9

I think it was a very wise decision to use a M.2 card because finding the “right” modem is a moving target. With the roll-out of 5G we may see changes also in the use of bands for 3G and 4G as operators revise their maps.


#10

this is in sydney - measurement apparatus goes only up to 3.5GHz according to the spec sheet :worried:


#11

We can assume that Gemalto is more credible than BroadMobi - quality control , etc.
But, since it lacks a few LTE bands for major US carriers, most of us needed alternative. Thank you for getting it !
Now, @nicole.faerber is this BroadMobi BM818 (US) fully certified for US carriers? What about VoLTE?
I pre ordered the phone long ago, but need to know if I’m making a right decision on modem.

Thanks


#12

The BM818-E1 bands are a strict superset of the PSL8-E, apart from 1 UMTS band, which is irrelevant, since all countries where the variant is useful use Band 1 only, which is supported by both.


#13

I’ve tried to match the Modems and Canadian providers.

Feel free to look it over and tell me if I’ve made any mistakes.


Librem 5 carrier compatibility thread
#14

It matters because of the choice of which countries you want to be surveilling you. Let’s say you are in the US. If you want China and the US to be surveilling you, choose the BM. If you want the EU and the US to be surveilling you, choose the PLS. :slight_smile:

All use of the cellular network is intrinsically insecure, and can be surveilled at various points (the cellular modem being just one of them). If you want security then use the cellular network to access the internet and layer your voice (and other) communications on top of an end-to-end encrypted protocol.

There is also a potential issue with tariffs if the trade war escalates (but that is really just “price” - see next).

So choose the cellular modem based on other criteria e.g. supported LTE bands, speed, price.


#15

Certifications are claimed here. http://www.broadmobi.com/en/module_show.php?id=18 Whether that is enough detail for you I don’t know.


#16

Freedom Mobile uses Band 13:

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.


#17

Apparently their website won’t let the VPN traffic in :slight_smile:


#18

You are correct. I’ve updated my image above. Thanks!


#19

I’m pretty sure wcdma is the underlying tech for UMTS (GSM 3G) the competing tech know as cdma is actually cdma2000. So i think all your providers are fully supported with the PLS8-US and BM818 on 3g.

So as fara as i can see you will only miss out on LTE B7. B8, B13, B29 and B66 seam to be edge cases for individual providers any ways.


#20

I believe you’re correct. A quick search shows they are the same. I’ll update the image again. Thanks!!