KISS TNC Bridge

Updated: November 9, 2026

Share one KISS TNC with many apps over Bluetooth LE and TCP.

KISS TNC Bridge comes in two forms:

The Linux daemon, kiss-tnc-bridge, runs on a Raspberry Pi or any other Linux computer. It shares one KISS TNC (the TNC in your radio over Bluetooth or USB, a serial TNC, or a software TNC like Dire Wolf) with any number of KISS TNC apps, over Bluetooth LE and TCP.
The ATOM Lite is a pocket-sized bridge between a radio's Bluetooth Classic TNC, like the one in the Kenwood TH-D75, and the KISS TNC apps on your phone, over Bluetooth LE. Install the firmware from your browser in a few minutes.

Both are free and open source, on GitHub. Announcing kiss-tnc-bridge explains why the project exists.

Vocabulary

These words mean the same thing everywhere in the KISS TNC Bridge project.

Bridge: A running KISS TNC Bridge, which shares a TNC with your apps. An ATOM Lite is one bridge. The Linux daemon can run several on one computer, each with its own TNC and name.
Pair: Introduce a radio to a bridge over Bluetooth Classic. Once paired, they connect automatically.
Connect: Create a link to or from a bridge. Connections can be made from the bridge to a radio, from a KISS TNC app to the bridge, or from a management app to a bridge.
KISS TNC app: Any application that can communicate with a TNC using the KISS protocol to do cool radio stuff. It could be an APRS app on your phone, or a winlink app on your computer. A bridge makes more TNCs useful to more KISS TNC apps. Sometimes we call these apps clients.
Management app: A program that changes a bridge's settings and shows its status. It's separate from the program that runs the bridge. ktbctl is the management app today. An iOS app is coming.
Authorize: Give a management app permission to manage a bridge, once, with the bridge's authorization code while it's in authorization mode. From then on the app can manage the bridge any time. Revoke takes the permission away. ktbctl on the computer running the Linux daemon, or connected to an ATOM Lite by USB, is authorized without the code.
Authorization code: The secret, 16 characters or a QR code, that authorizes a management app. Each ATOM Lite has its own, shown when you install the firmware. Keep it: you'll want it for each new management app. It stays the same until you change it or do a clean install.
Authorization mode: A few minutes when a bridge accepts one new management app. The bridge keeps working the whole time. On an ATOM Lite, hold the top button for 3 seconds: the light blinks magenta for up to 5 minutes, until an app is authorized, or until you press the button.