Chosing the right modem PLS8 vs BM818


#21

And i don’t know anything about canadian providers but here in germany the provider are going to fade out 3g the next 2 years and gonna reuse the frequencies for LTE and 5g.
So it might be of interest to lock which frequencies are used for 3g know and which LTE band could be used on the later an chekc them also. I See the 850 Band for example. Its used by many for 3g but only Telus uses it for LTE but this could probably change on the other providers.
The lower frequencies are also of more interest i expect as they have longer ranges per cell, and you have a lot of countryside.


#22

Consider the updates to the page https://puri.sm/faq/supported-networks/ where they say they are considering two variants of BM818. For example, they are considering BM818-A1 which supports other bands not supported by the BM818 such as Band 13

    Gemalto PLS8 BroadMobi BM818
Standard Frequency/Band PLS8-E PLS8-US BM818-E1 BM818-A1
GSM/GPRS/EDGE GSM 850MHz X X X
EGSM 900MHz X X X
DCS 1800MHz X X X
PCS 1900MHz X X X
HSPA+/WCDMA B1 2100MHz X X
B2 1900MHz X X X
B3 1800MHz X
B4 1700MHz X X
B5 850MHz X X X
B8 900MHz X X
LTE-FDD B1 2100MHz X X
B2 1900MHz X X X
B3 1800MHz X X X
B4 1700MHz X X
B5 850MHz X X X
B7 2600MHz X X
B8 900MHz X X
B12 700MHz X
B13 700MHz X
B17 700MHz X X
B20 800MHz X X
B25 1900MHz X
B26 850MHz X
B66 1700MHz X
TDD-LTE B38 2600MHz X
B40 2300MHz X
B41 2500MHz X X

The Librem 5 in France, which modem?
#23

If I can untangle all the indirect references, the only AT&T band the US modem is missing is B30.


#24

BM818-E1 has really broad support. Based on that it seems like a great upgrade from PLS8-E. Is there another difference between the two like speed or something?


#25

There is a good comparison in the second post of this topic. See above. The BM is faster, as it happens.


#26

Option 2: Broadmobi BM818 (made in China)

IMHO,
when it comes to a sensistive component such as the modem :

made in China = designed by Chinese
representing disrespect to our privacy and data security -

which is what Purism is trying to avoid
and the reason why we willingly give up the advantages of Android
and pay dearly to become Purism backers

Quote from BM818 operation_manual
https://fccid.io/2AON8-BM818/User-Manual/BM818-Coperation-manual-V1-4-4107101

“Copyright notice :
All right reserved : Shanghai broad Mobi Communication Technology Co Ltd
… and it is protected by Chinese law…”

Am i wrong ?


#27

I gotta say Im not at all happy about having to use a chinese modem myself. The Gemalto did not support my bands so I guess im stuck with it for now . Hopefully someone will find some obscure electronics manufacturer US based or atleast not chinese that will be compatible down the road. I’ve been looking for an alternative myself.


#28

What about this ? https://y1cj3stn5fbwhv73k0ipk1eg-wpengine.netdna-ssl.com/wp-content//uploads/2017/11/Telit_LN940_Datasheet.pdf

Im kinda a hardware newb with cellular modems . What attributes should I be looking for in an M2M M.2 modem with voice support .

Specifically what indicates cellular voice calling as opposed to volte ?


#29

I’m not 100% but I don’t think that one would work. Seems to use PCIe bus on the m.2 interface. In my search for the same thing, I’ve noticed they usually indicate voice and VoLTE as a supported feature in the specs.


#30

I think voice support is the problem. I believe its one of the many that is only meant for data , such as in notebooks. If you ate looking for modems look for any mentioning of voice or VoLTE (VoiceoverLTE) in the specs.


#31

Does anyone have a relyable source listing the various mobile band per european countries?

According to this site, https://www.gsmarena.com/network-bands.php3?sCountry=Belgium,
and if I read the table from the purism faq correctly, some bands are not supported by the proposed hardware.


#32

Try https://www.frequencycheck.com/


#34

I’m also looking for a good overview graphic. Best thing so far are two tables from wikipedia here and here

This site also has graphical representaions but only by country. So cross country comparison is also tedious.

So what i read so far for europe is:

B1 2100MHz 3g (subject to be repurposed for LTE)
B3 1800MHz LTE (repurposed from GSM )
B7 2600MHz LTE
B8 900MHZ GSM / 3g
B20 800MHz LTE
B28 700MHz (old TV (dvbt) and wireless microphone frequencies) 5g which will probably be compatible with 4g i think

B22 B42 B48 3500/3600MHz lies in the 5g spectrum (3.4-3.8 5GHz) but could also be used for 4g
B32 1500MHz some limited use in few eu countries
b40 2300MHz also only few countries

So i see us only miss out on the B28. Which is a shame as it is an additional low frequency band, which are good for long distance and good building penetration and will grant for good coverage in the near future as it will be much cheaper to deploy than the many high frequency cells need for high-speed 5g.

And this graphic from here for 5g and as far as i know there is some kind of compatibility between these two. So The big thing here is again the B28 700Mhz Band


#35

Strange that https://puri.sm/faq/supported-networks/ missed B3 for BM818-E1 but http://www.broadmobi.com/en/module_show.php?id=18 have it.
For me B3 is main freq in my country.

Gemalto PLS8 is to old without TDD-LTE support :frowning:


#36

I have a spec sheet for E1 variant, but it is possible that I missed B3. I will check out once again and edit the FAQ entry if needed.

Update: No, the FAQ entry information correspond to the spec sheet.


#37

That very strange and sad for me that BM818-E1 dont support 1800MZh

I found some leaked docs for BM818-A1 on tests https://fccid.io/2AON8-BM818
There you can see many interesting info about quality of BM818.

In https://fccid.io/2AON8-BM818/Internal-Photos/B18W50495-BM818-Internal-Photos-4107093 you can see that BM818-A1 based on Qualcomm MDM9607 LTE modem (And as I know all IT in Singapore controlled/surveilled by USA).

Recently in Qualcomm chips discovered some vulnerabilities https://blade.tencent.com/en/advisories/qualpwn/
Qualcomm reported that MDM9607 affected by many vulnerabilities https://www.qualcomm.com/company/product-security/bulletins
Does BroadMobi update Qualcomm firmware for chip?


#38

Can you summarize ? Im not sure exactly what im looking at here.


#39

The BM818-E1 does support 1800 MHz (at least the most common variant, which is 3gpp band 3).
If the confidential datasheet that Purism has doesn’t mention this, it is likely a mistake in that datasheet and not in the website (which explicitly mentions it), since B3 support is basically a hard requirement for a EU/International variant that does dual-band GSM (which is 900 MHz B8 and 1800 MHz B3).

In Singapore, US surveillance isn’t the major issue, Singapore itself is one of the more surveillance-intensive states and the government itself is known to keep taps on communication in the country.
Of course there are still US interests, and also Chinese interests.
The BM818 combines both, since the Chipset and most of the software comes from Qualcomm in the US, and the other parts of the software (operating system services and some more) from Broadmobi.

The Qualcomm vulnerabilities are nothing unexpected, every modem manufacturer will have them, since they all run very complex software.

These vulnerabilities will themselves not directly apply to the Librem, because it doesn’t use the Qualcomm-integrated stack and so cannot be attacked by the same chained exploits.

However, the “Respects Your Freedom”-badge from the FSF, which Purism strives to achieve, prevents Purism to ship firmware updates for the modem, since that would require Purism to ship non-free firmware.
This could lead to future exploits at least for the modem portion (though the OS is unlikely to be attackable from that angle).


#40

which is not to say that you couldn’t download and apply a firmware update yourself, given appropriate knowledge and tools.

I note also that the BM claims FOTA support, so it might happen without your knowing about it 8-|

(whereas the PLS8 says “firmware update via USB”).

I’m sure there are aspects to look into.


#41

Oops. I messed up 3G and 4G table sections.
in FAQ BM818-E1 support B3 for LTE but not support B3 for HSPA+
I check again my operators. I dont need B3 for UMTS, only for LTE and 2G
So that’s all okay for me, BM818-E1 is fully compatible with my country.
And Purism FAQ is correct for BM818-E1.
But may be mistake in FAQ in PLS8-E for HSPA+ B3. How PLS8-E support B3 for 3G?? May be it possible and uses in some counties. :confused: I hear only about compatibility GSM+LTE signals for B3 (1800MHz) not for 3G