Now I am aware this is not a super up to date modem, and from searching for hours on this problem, not something people are using often outside of their Lenovo laptops.
I have bought a M.2 to USB adapter, fitted the EM7345, a working SIM, and connected the USB cable to my Pi 3b.
I have very very little linux knowledge.
If I run ifconfig, there is a wwan0 section that has my Sierra Wireless EM7345 listed, but only 26 bytes sent, and none received.
The WAN light on the unit lights, yet I am unable to get a reply when I do
ping -I wwan0 188.8.131.52
I understand I am supposed to be using the cdc_wdm driver in some capacity.
I have used the card on Windows 10 and it connects and I am able to access the internet. I have updated the card to its latest firmware and run “EM7345_MBIM_ACM.exe” to unlock the AT command port.
Pulling my hair out now. My end goal is just to share the internet connection from this now USB modem with a router, and since the router is not OpenWRT capable, I am having to use the Pi 3b as a bridge, to first have connectivity to it, then to forward the connection through its ethernet port - the latter I can probably accomplish.
If you are curious what M.2 to USB converter I am using, it is one of these. They have no active electronics inside (no microcontrollers on either side of the board.) NGFF M.2 To USB 3.0 Adapter with SIM Card Slot for WWAN/LTE/4G Module (Including the Outer Case)-buy at a low prices on Joom e-commerce platform