Hi,
am looking for OpenWrt support for a LTE modem/router/USB stick. At least 300/150 dl/ul speed (Cat6/7...???).
For example Huawei B535.
This is the table with some LTE modems already supported by OpenWrt, but it is sometimes hard to find which speeds are supported. AFAIK, most of them support 150/50 speeds.
Best regards.
Almost any [GigE capable] router with miniPCIe slot + the modem card in such form-factor or M.2 card with adapter.
For 150Mb UL support you will need at least a Cat-12 modem.
Right, it was 300/100, so Cat 7, which the Huawei B535 supports.
So, there are M.2 LTE modules.
Can you send a link of a Cat 7 M.2 LTE module which is compatible with OpenWrt?
My router has no miniPCIe slot but USB. I could use M.2 USB adapter and connect on my router.
Found the instruction:
https://openwrt.org/docs/guide-user/network/wan/wwan/ltedongle
The M.2 USB module:
Still looking for M.2 module with the speeds.
Since you're going to use a USB adapter you can choose between mPCIe and M.2 (NGFF) modems (and adapters). Potentially you can use almost any modem supporting protocols like MBIM/QMI/NCM. Take a look at Quectel's EM12 or EP/EM06 or Sierra Wireless EM7455 (Cat-6).
EM7455, very interesting and good price, and found this one:
T77W676 450/50 speed.
In this forum
https://forums.whirlpool.net.au/archive/3vx1k1r3-11
they say it has mbim configuration. So, it should work 
There is another one, Qualcomm X20 T77W968, but much more expensive.
Perhaps, you can recommend a specific M.2 LTE USB Adapter?
The one you mentioned last time works just fine, but it is USB2. For USB3 adapter recommendation try to search in that whirlpool topic within last month.
Careful. Cat12 LTE modems typically require a lot of power. The Sierra Wireless EM7455 for example draws a max of 1.5A at 3.3V, which means 990ma from the 5V USB supply (and that's assuming 100% efficient conversion of 5V to 3.3V)
USB2 supplies 5V at a max of 500ma, and USB3 supplies 900ma. Therefore, to insure enough power for a Sierra Wireless EM7455, your USB modem enclosure would need TWO USB connectors (one for data+power, the other for power) in order to get 900mA to the modem. And even then, if the USB jacks are USB2, you'd be right on the edge of enough power.
I haven't looked at other cat12 modems, but I'd expect their power requirements to be similar.
EM7455 is Cat-6 modem and it works fine with the enclosure mentioned above.
A quick look at the documentation tells us that the maximum consumption will be 1A @3.7V with full Tx Power and 2xCA active. For devices with weak USB ports usage of Y-cables could be recommended.
Cat-12 modem will require USB3 enclosure with optional additional power input.
That have nothing to do with OpenWrt.
Found this one
Oops, I had the wrong datasheet in hand, but the datasheet for the 7455 says the max current draw is 1.5A (page 47 of the technical specs), although they say the maximum average current is 1A.
The specs for the ltefix.com M.2 USB enclosure here says 3.3V.
The moral of the story is that powering LTE modems via USB isn't plug and play. If you want to make sure your LTE modem doesn't periodically crash, make sure your power source can handle it.
And if you are looking to power a high performance LTE modem from USB2, you'll definitely want two USB connections.
Oh, BTW, ltefix.com is shutdown due to supply chain disruption. They were selling stuff on facebook, but they've shut that down too. The last I heard from them, they hoped to be back in business in a couple of weeks.
Short and good USB cables are also essential. Most USB data cables aren't made for 1A currents, leading to significant voltage drops. The modem brownout protection will reset the modem, looking like a crash. This can be very confusing because of the constantly varying power requirements of LTE modems. The "crashes" often appear to be related to external events, like handovers or high rate data transmission. You can spend a lot of time trying to figure out why the modem "crashes" only under some specific condition, when the solution is as simple as replacing the USB cable.
BTDT...
Ok, so finally I've decided to build an OpenWrt based modem:
Main components:
The T77W676 does not support the required LTE bands 1+3+7+20+28.
Does Openwrt support Intel XMM 7262/7360 e.g. Fibocom L850-GL?
Found this thread:
https://www.mail-archive.com/modemmanager-devel@lists.freedesktop.org/msg05983.html
Can sb. confirm that XMM modules work with OpenWrt?
Thank you for the information!
PCIe mode is not supported. They should work in USB mode if they allow switching to that.
The Intel based modems are cheaper for a reason. Not something I'd recommend. I have bought one (XMM7160 based) myself many years ago, and won't repeat that error.
OpenWRT isn't fully baked on RPi4. I've been playing with this community build: Rpi4 < $(community_build)
Also, I recommend using a USB enclosure that has two USB connectors like the one that ltefix.com sells (unfortunately, they are shut down right now). The spec sheet for the 7455 says the maximum current draw is 1.5A which is 4.95W. USB3 supplies 5V a max 900ma. Even assuming a 100% efficient 5V -> 3.3V conversion, USB3 can only supply 4.5W.
Thank you @bmork. But EM7455 should work (in USB mode) as AndrewZ recommended this module?
Does EM7455 has any carrier/vendor limitations?
Need Telefonica/O2 compatibility. The only LTE band that is not supported is 28.
Are there any branding limitations if I use a Dell DW5811e?
Yes, ltefix.com is the only provider of that kind of USB adapter with two connectors that I could find. Found USB power Y-adapters.
Yes. My laptop has one of those, so it's pretty well tested with the Linux drivers 
I'm not sure you need to worry too much about 900mA @ 5V being less than the specifed peak. The issue is more like having only USB2 (500mA) and a cable voltage drop of 1V or more. You don't necessariy need a Y cable or multiple cables.
FWIW, I am using a EM7565 in one of these adapters (the IT-NBU3A version) connected to the USB3 port of a WRT1900ACv1 using a 50cm USB3 extension cable: https://www.aliexpress.com/item/32794435102.html I haven't seen an unexpected reset yet. But this might obviously depend on my network conditions, which are pretty good.
5v T 2200 ()
___poly_____________/
| |
. . . . . _____
. . . . . -
-
_____
Thank you guys.
Hardware arrived, LTE works with the Sierra module. The T77W676 doesn't work at the moment.
How can I bridge the pi (used as LTE modem) and forward wan/public ip to my router?
Modemmanager is used as the interface.
Please use this forum category only for hardware recommendations.
For further questions regarding configuration, please open a new topic.
Thanks!