ModemDeck Linux by MilMit

Website: https://milmit.net

Native Linux control for cellular modems — LTE, TD-LTE, 4G+, APN, SIM, messaging and diagnostics.

ModemDeck is a lightweight native GTK4 cellular modem manager for Ubuntu/Linux, developed by MilMit. It uses ModemManager/NetworkManager and small event-driven helpers instead of an Electron/Chromium runtime or a continuous mmcli polling loop.

Tested RC release

The currently tested package is v1.0.0-rc1.4.1. It has been built successfully by GitHub Actions and installed successfully on the target Ubuntu system.

Download the Debian package from the GitHub Releases page and install it with:

sudo apt install ./MilMit-ModemDeck-1.0.0-rc1.4.1-amd64.deb

Release page: https://github.com/MilMit/modemdeck-linux/releases/tag/v1.0.0-rc1.4.1

What RC1 includes

Radio dashboard

• Multi-modem detection and hot-plug updates through ModemManager D-Bus.
• 2G/3G/4G/4G+/5G display when the available telemetry can prove that state.
• RSRP, RSRQ, SNR, RSSI and a separate radio-quality assessment.
• Signal history.
• Serving LTE band, FDD/TDD, EARFCN, PCI and channel bandwidth when available.
• Structured carrier aggregation: PCC/SCC components, 2CA/3CA topology and component channel bandwidth.
• GNOME top-bar integration plus optional low-overhead background monitor.

Safe band controls

• Auto / LTE-FDD / TD-LTE presets.
• Custom supported-band selection using ModemManager SetCurrentBands.
• 45-second confirmation window.
• Local pre-change backup.
• Persistent pending transaction.
• Detached rollback guard that survives a GUI crash and restores the previous selection if it is still unconfirmed.
• Bounded safety-backup history.
• LTE cell-lock stays preview-only until model/firmware-specific write/recovery behavior is verified.

Band profiles

Built-in profiles:

• Auto
• B42 TD-LTE
• B1+B3+B7

You can also save/delete your own profiles. Optionally, the active profile is restored after reboot and after suspend/resume by the lightweight user service.

APN Manager

NetworkManager-backed GSM/APN profiles can be:

• listed
• created
• edited
• activated
• deleted

APN username and an optional password are supported. Password values are handed directly to NetworkManager and are not stored in ModemDeck's own config. Existing passwords are never read back into the UI.

SIM security

Through the standard ModemManager SIM interface:

• unlock SIM with PIN
• enable PIN protection
• disable PIN protection
• show current SIM lock state/slot when reported

Live traffic and data usage

• Live RX/TX rate from /sys/class/net/<interface>/statistics/*.
• No speed-test traffic is generated.
• Daily and monthly local byte accounting.
• Reset control.
• Local history is bounded to prevent unbounded config growth.

Accounting is active while the GUI or optional background monitor is running.

Desktop/system integration

• Suspend/resume detection through systemd-logind.
• State resync and optional profile restore after resume.
• Modem USB/internal WWAN hot-plug handling.
• Optional notifications.
• systemd --user monitor.
• GNOME top-bar extension.
• Desktop launcher.
• .deb build script.

Support, updates and privacy

• Supported Modems/capability page.
• In-app release notes.
• Update check against https://milmit.net/modemdeck/update.json.
• server/update.json.example for publishing the manifest on MilMit.
• Report-a-problem / MilMit website integration.
• Privacy-safe diagnostics export: IMEI/equipment IDs are intentionally omitted.
• English/Persian language preference and translation infrastructure.
• MilMit About/website/package metadata.

Verified Dell/Foxconn DW5821e results

Testing on the target Ubuntu laptop has verified the T77W968 / DW5821e Snapdragon X20 LTE path:

• FDD LTE B1 serving carrier.
• 3CA • B1 + B7 + B3, each component reported as 20 MHz.
• Real TD-LTE band lock to B42.
• B42 EARFCN 43292 / PCI 89.
• 2CA • B42 + B42, each component reported as 20 MHz.
• Vendor radio details through a direct read that temporarily inhibits and then returns the modem to ModemManager.

A sum such as 40/60 MHz is component channel bandwidth, not an internet speed estimate.

Multi-vendor architecture

Generic ModemManager support is used whenever possible. Advanced telemetry is capability-gated rather than guessed. Driver profiles exist for:

• Dell/Foxconn DW5821e / T77W968
• Quectel
• Fibocom
• Sierra Wireless / AirPrime
• Huawei
• Telit / Cinterion
• SIMCom
• Generic MBIM/QMI fallback

Support varies by exact modem and firmware. Controls that are unsupported or not verified stay disabled.

GitHub releases

GitHub Actions builds packages on every push to main. The workflow also publishes/refreshes a nightly prerelease with the latest binaries. Version tags (v*) create versioned releases containing:

• MilMit-ModemDeck-<version>-amd64.deb — recommended Ubuntu package
• MilMit-ModemDeck-<version>-x86_64.AppImage — portable build
• MilMit-ModemDeck-<version>-linux-source.tar.gz — source snapshot
• SHA256SUMS.txt — checksums for release assets

See docs/PUBLISHING.md to publish the repository and create a release directly from Ubuntu.

Build on Ubuntu

Install development/runtime dependencies:

./scripts/install-deps-ubuntu.sh

Build and run:

cargo run --release

Run the lightweight monitor alone:

cargo run --release -- --monitor

Install for the current user

./scripts/install-user.sh

This installs the binary, desktop entry, user systemd unit and GNOME extension files when GNOME is present. Enable/disable the monitor from Preferences.

Build a Debian package

./packaging/build-deb.sh

The .deb is written under target/.

Self-check

./scripts/phase5-selfcheck.sh

It checks ModemManager, NetworkManager tools, PolicyKit helper availability, update-check dependency, user monitor/indicator installation and current process resource usage.

Translation

Preferences support System / English / فارسی. The main UI is translated through stable translation keys plus a migration layer for legacy labels. Language changes are applied on restart.

Update manifest on milmit.net

Copy server/update.json.example to the web location used by RC1:

https://milmit.net/modemdeck/update.json

Update version, url and notes for each release. ModemDeck sends no analytics in this check; it only downloads that small JSON manifest.

Privacy and logs

• Diagnostics omit IMEI/equipment IDs.
• APN passwords are not stored in ModemDeck settings.
• No verbose persistent AT response logging by the monitor.
• Runtime status contains display-oriented state only.
• Data usage is stored locally in the user's config directory.

Important safety behavior

Vendor deep reads may temporarily inhibit ModemManager and can briefly reconnect mobile data. They are therefore manual rather than high-frequency background operations.

Band writes are guarded by backup + persistent transaction + detached rollback process. Cell-lock writes remain preview-only in RC1 because persistence/recovery behavior is vendor/firmware-specific.

Uninstall user installation

./scripts/uninstall-user.sh

Communications in RC1.2

The main window is split into focused tabs instead of one long page. SMS, Voice and USSD controls are capability-gated at runtime. ModemDeck only enables a feature when ModemManager exports the matching standard D-Bus interface for the selected modem.

SMS supports on-demand inbox loading, sending and deleting. Voice supports dialing, answering and hangup when the Voice interface exists. Voice call control and voice audio routing are treated as separate capabilities; some WWAN modules can expose call control without a usable host audio route. USSD supports initiate/respond/cancel when available.

End-user installation (RC1.3)

For normal users, do not run the developer dependency script. Distribute either the .deb or AppImage release artifact. The .deb lets Ubuntu install required OS runtime services automatically; the AppImage bundles ordinary application libraries and uses the host ModemManager/NetworkManager/Polkit services. See PORTABLE.md.

Smooth live updates

Starting with RC1.4, routine ModemManager signal/property events patch the visible labels and progress bar in place instead of rebuilding the full GTK modem page. Structural refreshes are reserved for modem add/remove, manual refresh and explicit configuration operations.