StarTech.com USB to Null Modem RS232 DB9 Serial DCE Adapter Cable with FTDI - ICUSB232FTN - Serial Adapters - CDW.com
ICUSB232FTN Startech, Adapter Cable, USB to RS232 DB9 Serial, with FTDI | Farnell Belgium
ZTE MF833V 4G LTE USB Modem Dongle, an IoT Device, France | Ubuy
External USB 2.0 Fax/Data Modem 56K V.92 - Bluetooth & Telecom Adapters | Networking IO Products | StarTech.com Belgium
B3181] ZTE MF833V (Customized Version Covering Global Bands) 4G LTE Mobile USB Modem Dongle, an IoT Device., Computers & Tech, Parts & Accessories, Networking on Carousell
USB Modem RJ45 3G 4G Mini Wireless Router Portable Universal Mini WiFi Router 150Mbps High Data Transmission Speed, Compatible with iOS Andriod Windows Linux, Plug and Play : Amazon.com.be: Tools & Home
Howto: Configure Telit Modem on Linux
This dirt cheap 4G LTE modem on a USB stick can be hacked to run mainline Linux - Liliputing