3G/4G modems - Alternatives?


Thank you for the link.

Honestly the information has confused the matter further.

If they are developing the phone using mPCIe they should continue to use that for the phone. There are a lot more mPCIe cards than M.2 available.

The information from Purism says the M.2 card using the PLS8 will have the uSim slot onboard.

I can’t find a single M.2 card that uses the Gemalto PLS8 modems.

Are they having custom M.2 cards made? If so why not have a global band option as well?


Yes i think gemalto is making one for them, maybe not exclusively but back when they told which modem and wifi they chose it sounded to me like they where both at least some kind of custom jobs.
The reason for that and the m.2 over miniPCIe is the size i think.
pcie needs 30mm width while 22mm is common in m.2 and could even go down to 16mm, thought i couldn’t find actual cards in this size and hope the stick to the standard to keep the slot usable for other cards. Same for the length. miniPCIe has 50mm or the half size 26mm while m.2 has alot more options including shorter ones.
But i hope both m.2 slots will be at least m.2 2230 as this seams to be a common size for m.2 cards. This would be just marginally small than the 30mm x 26mm mpcie but i think it could make the difference especially the smaller footprint of the connector which has to sit on the main pcb.

And although you are right that there are a lot more mPCIe cards available now, i think the future is m.2 and the L5 is probably not gonna see that frequent major updates, by which i especially mean major pcb layout changes like connector and interface changes. as this need so much testing and time. So i don’t expect any updates here for 3-5 years and for this time the connectors need to be able to hold updated modems and wifi cards to do minor updates here. So i like the choise of m.2 connectors for both.

But as i don’t have any more information than publicly available, this is mostly my speculation.


Gemalto lives in Munich, Bayern, Germany. That’s why I referred to Decision (EU) 2017/899 of the European Parliament and of the Council of 17 May 2017 on the use of the 470-790 MHz frequency band in the Union. And, as stated, there must be “justified reasons for a delay in allowing the use of 700 MHz frequency band for terrestrial systems capable of providing wireless broadband electronic communications services later than 30 June 2020”. So, please find a qualified player that EU is looking for if you want to join and win this game announced in May 2017.


I had a long chat today with the rep from Quectel. M.2 with a Sim card slot on the module is not going to happen. From any supplier. The back of the module is needed for heat dissipation.

Except for slim devices such as laptops, 2 in 1s and tablets mPCIe is going to remain the defacto form factor for cellular modem modules. It’s a practicality thing for them.

I was asked not to discuss price particulars but the EM06 is not as expensive as the prices being floated around

The rep is passing on my details to a distributor to discuss our situation further.

At it’s most basic however an M.2 LTE card with Sim card slot isn’t happening.


SIM card slot is not on the module on the Librem 5


Wow. Really cool of you to reach out to them. Really valuable information. Thanks.

Thought i still do not understand this in total, as all modems i used and have seen ( all in notebooks) hadn’t any sim slots and where blank on on side i think, but all of them were mPCIe. So i don’t see the advantage here. As m.2 provides similar sizes. But they will know what they do.

And as @Caliga said its the same with the L5. No simcard on the modem needed. It would only be cool for dual sim.


Baseband : Gemalto PLS8 3G/4G modem w/ single sim on replaceable M.2 card

Librem 5 ordering page


That info is probably as old as the campaign. I thought so until Dorota said otherwise. I guess it is outdated, kind of obvious if no such module actually exists!?


The information seems to be a bit all over the place. I guess untill Purism says something official we won’t know. In saying that there is no current Gemalto PLS8 M.2 modules which would suggest the one one being used by Purism is custom.


But if the module used by Purism is custom, and has the sim slot on it, this means that no other standard modem can be used, because there’s no other one with the sim slot on it. So if we use another modem, we would end up with a phone that has no sim slot. :thinking:


@Caliga, even though your reaction is just a little bit late I am thanking you for bringing us to the right path. I noticed myself this issue but didn’t react at all. Now when it is all clear I hope @36w4r6 will continue with his great work of finding the best solution for B28 band on M.2 expansion slot.


But it could be custom (in order to get M.2) but without a SIM slot. Until someone from Purism wants to provide actual information it’s all just speculation.


It doesn’t say that the SIM card slot is intergrated on the modem M.2 Card (it’s not).
It says that the first version of the L5 can’t handle more than one SIM.


I think they repeated the info sufficiently often. No slot on it, not custom made.

Basically says, if the m.2 module you find is supported on Linux, has the desired bands and codecs n stuff, it’ll work.
So summary:

  • nobody sells m.2 modems with SIM slot
  • Purism has that slot on the mainboard
  • every standard module is a possible candidate


It’s really the modem chip that handles the number of Sims. The PLS8 can handle 2 Sims.

2 UICC (SIM/MIM) interfaces 1.8V / 3V from Rel.3.0 onwards and for PLS8-X /-VSerial Interface (UART)

As taken from the PLS8 documentation.


This is in general correct bt as already has been stated here, the M.2 cards do not come with SIM slots nor eSIM (embedded SIM) so all SIMs need to be placed on the phone side (mainboard). There we have space constraints for only one SIM car, I’m afraid.



I don’t plan on stopping. Also feel welcome to contribute to the list of options if you find one.

One thing I have noticed while talking to suppliers (manufacturers and designers not distributors) is a lot of what’s advertised online is inaccurate and no longer available. Also prices are considerably higher than they should be.


The Quectel units are eSIM capable. The problem as described to me is that carriers haven’t taken up the system yet.


Well, OK, let’s say, if the eSIM is included in the M.2 card, then it could work, though we (Purism) will not have software for that any time soon. Managing the eSIM is non trivial (to get the authorization data from the provider into the eSIM etc.).



I wasn’t suggesting that it be used. Not that it can be used. The only device with approval anywhere to use eSIM with carrier switching is the iPad.

I was just pointing out that the manufacturers and designers already include this feature if it becomes an option.

While I have your attention can we confirm a few things if possible?

Is the SIM card slot on the main board?

Does the design allow for the high/low voltage detection of a SIM card?

Is it only the USB 2 interface that is being used on the PCIe bus for data?

Are the PCM channels being used for non VoLTE voice audio?

Thank you in advance.