Get Raspberry Pi to connect to 4G LTE Cat1 Cellular using ConnectedIO modem
The EM1000T-VZ-CAT1 modem can be set to run in either AT command mode (AT#USBCFG=0) or MBIM mode (AT#USBCFG=3 or 5) If you're just starting out, we suggest MBIM mode (AT#USBCFG=3 with ModemManager/NetworkManager see below)
The Raspberry Pi (as of Buster 12/2020 release) uses a hybrid network configuration/management model that uses old Debian networking (/etc/network/interfaces) and dhcpcd (both configured to run as systemd services). It does not come configured for systemd-networkd or NetworkManager (2 of the other ways of doing Linux networking).
The 2 ways we've been able to get this modem to work on the pi are:
- Using /etc/network/interfaces and specifying an 'up' script in the manual configuration stanza, and
- Using ModemManager (1.14.0 or higher) and NetworkManager
At the time of this writing, Number 1 is the method recommended and supported by ConnectedIO, wheras Number 2 is recommended here (by us). Either of the modem modes can be made to work in either of these scenarios, but we recommend AT mode for Number 1 and MBIM mode for Number 2.
For a recipe to configure /etc/network/interfaces using the modem in AT command mode, install 'StartDataCM4NA.sh' and 'at.sh' scripts and use 'interfaces.txt' as a guide for your entry in /etc/network/interfaces. Note: the above scripts may require tweaking (e.g. install ppp package to gain 'chat' command)
For a recipe to configure ModemManager and NetworkManager with the modem in MBIM mode, see this file