Connect a Raspberry Pi to the internet using a Hologram SIM

Requirements

A Raspberry Pi, with a mouse, keyboard, and monitor for the initial setup.
A cellular modem with an activated Hologram SIM and a data plan. If you have not activated your SIM yet, see Activate your first SIMs.
NetworkManager (nmcli), pre-installed starting on Debian 12 (bookworm).
ModemManager (mmcli), pre-installed starting on Debian 12 (bookworm).

Connect the Raspberry Pi

Verify the required packages are installed

Confirm that both mmcli and nmcli are available:

which mmcli
which nmcli

Both are installed by default on Debian 12 and later. If either is missing, install it:

# NetworkManager
sudo apt-get install network-manager

# ModemManager (note: the Raspbian package name is all lowercase)
sudo apt-get install modemmanager

Set up WiFi or Ethernet first (older OS versions only)

On Debian 11-based and older images, set up your network connection with NetworkManager before continuing, so you do not lose access to the device. Newer images do this automatically, and this step is not needed if you use Ethernet.

Important: Set up WiFi while the Raspberry Pi is connected to a monitor, keyboard, and mouse. You can lose remote access after installing nmcli. If you used the Raspberry Pi Imager, you can set the WiFi SSID and password there until you can set up Ethernet.

# Check connections
nmcli device
nmcli device show wlan0
nmcli connection

# Enable WiFi
nmcli radio
nmcli device wifi list
nmcli device status

# Connect to WiFi
sudo nmcli device wifi connect <your-wifi-ssid> password "<your-wifi-password>"
nmcli device status
nmcli connection show

# Verify the services are running (you may need to restart first)
sudo systemctl status ModemManager
sudo systemctl status NetworkManager

Connect the modem to the Raspberry Pi

Insert your activated SIM into the modem, then connect the cellular modem to your Raspberry Pi via USB.

Confirm the modem is detected

Verify that the Raspberry Pi detects the modem:

lsusb

lsusb output listing the connected cellular modem as a USB device

Connect to the network with ModemManager

Connect the modem to the network using ModemManager and your APN:

# Get your modem ID
mmcli -L

# Verify your modem details
mmcli -m <your-modem-id>

# Connect the modem to the network
sudo mmcli -m <your-modem-id> --simple-connect="apn=<your-apn>"

# Verify the changes
mmcli -m <your-modem-id>

mmcli output showing modem details before connecting

mmcli output showing the modem connected to the network after simple-connect

Add the connection to NetworkManager

Adding the connection to NetworkManager sets up the correct IP routes.

# Look for the GENERAL.TYPE and GENERAL.DEVICE values for the next step
nmcli device show

nmcli device show output highlighting the GENERAL.TYPE and GENERAL.DEVICE values

Create the connection, replacing the placeholders with your own values:

<primary-port> — the GENERAL.DEVICE value from the previous command.
<your-connection-name> — any name you choose for the connection.
<your-apn> — the APN for your SIM.

sudo nmcli connection add type gsm ifname "<primary-port>" con-name <your-connection-name> apn <your-apn>

# Verify the changes
nmcli connection show

# To update an existing connection with other modem details:
# sudo nmcli connection modify <your-connection-name> ifname "<new-primary-port>" apn <your-apn>

# For more options and how to use them:
# nmcli connection --help

nmcli connection add command creating a new gsm connection

nmcli connection show output listing the new gsm connection

Note: The type gsm connection works well with Verizon SIMs too, as long as your modem is Verizon certified and you use the correct Verizon profile type (Cat-1+ vs. Cat-M).

Confirm the modem connection is active

Confirm the modem connection appears in NetworkManager on the correct TYPE and DEVICE, and shows as connected (green):

nmcli connection show

nmcli connection show output with the cellular connection active and shown in green

Verify the IP interface

Confirm your IP table has the appropriate wwan0 or ppp0 interface, including the SIM’s IP address:

ip a

ip a output showing the wwan0 interface with the SIM's assigned IP address

Run a ping test

Test the new connection by pinging hologram.io. Replace <your-ip-interface> with the appropriate interface (wwan0 or ppp0):

ping -I <your-ip-interface> hologram.io -c 5

ping output showing successful replies from hologram.io over the cellular interface

(Optional) Confirm internet access over cellular

Turn off the Raspberry Pi’s WiFi and open a site such as https://www.google.com in a browser.

Congratulations! Your Raspberry Pi is now connected to the internet through your cellular modem.

Troubleshooting

General troubleshooting commands

Use the built-in help for each tool to explore available options:

# More info: https://manpages.ubuntu.com/manpages/bionic/man8/mmcli.8.html
mmcli --help

# More info: https://manpages.ubuntu.com/manpages/kinetic/en/man1/nmcli.1.html
nmcli --help

Add IP routes manually

If these or other tools are giving you issues, the device most likely does not have the correct routes configured. Add them manually with the commands below. You need to re-add these routes every time the device boots, unless you use the Hologram SDK, which configures them automatically.

# These routes apply to all Hologram SIMs, regardless of the upstream partner: 10.176.0.0/16 and 10.254.0.0/16
# Replace <ip-interface> with the appropriate value (wwan0, ppp0, etc.)
ip route add 10.176.0.0/16 dev <ip-interface>

# This route also lets you use Spacebridge while on WiFi
ip route add 10.254.0.0/16 dev <ip-interface>

# Verify
ip route

ip route output showing the manually added Hologram network routes

Run AT commands through ModemManager

You can put ModemManager in debug mode to run AT commands directly through it:

# Find the service file
ls -lrt /lib/systemd/system/ModemManager.service

# Find the line that starts with ExecStart and add --debug at the end.
# It should end up looking like:
ExecStart=/usr/sbin/ModemManager --debug

# Restart the ModemManager service (or reboot the Raspberry Pi), then run AT commands like this:
sudo mmcli -m 0 --command='+cgmi'

# Note: registration status commands are not shown in mmcli responses but
# logged in the Linux system logs and can be accessed with one of the below
# depending on the OS version:
# Debian 11 or older
cat /var/log/syslog | grep -i "+cereg:" | tail -1
# Debian 12+
journalctl -u ModemManager | grep -i "+cereg:" | tail -1

Optional: AT command access alongside the cellular connection

By default, ModemManager claims all AT-capable ports on the EG25-G, which prevents external tools from accessing them. The fix is to free up ttyUSB3 with a udev rule while leaving ModemManager in control of ttyUSB2 for the cellular connection.

Create the udev rule

sudo nano /etc/udev/rules.d/99-quectel-at.rules

Add the following line:

SUBSYSTEM=="tty", KERNEL=="ttyUSB3", ENV{ID_MM_PORT_IGNORE}="1"

Apply the rule

sudo udevadm control --reload-rules
sudo udevadm trigger
sudo systemctl restart ModemManager

Verify

sudo mmcli -m 0 -v | grep ttyUSB

Expected output:

ports: cdc-wdm0 (qmi), ttyUSB0 (ignored), ttyUSB1 (gps),
       ttyUSB2 (at), ttyUSB3 (ignored), wwan0 (net)

ttyUSB3 is now permanently free for AT command tools such as minicom or AT Command Wrangler, while the cellular data connection continues running on ttyUSB2. The rule persists across reboots automatically.

Port reference

Port	Role
`ttyUSB0`	Diagnostic (QCDM) — not AT
`ttyUSB1`	GPS/NMEA
`ttyUSB2`	AT — used by ModemManager
`ttyUSB3`	AT — free for your use
`cdc-wdm0`	QMI interface
`wwan0`	Network interface

​Requirements

​Connect the Raspberry Pi

​Troubleshooting

​General troubleshooting commands

​Add IP routes manually

​Run AT commands through ModemManager

​Optional: AT command access alongside the cellular connection

​Port reference

Requirements

Connect the Raspberry Pi

Troubleshooting

General troubleshooting commands

Add IP routes manually

Run AT commands through ModemManager

Optional: AT command access alongside the cellular connection

Port reference