# Bluetooth Log Viewer

> Securely view device Zephyr logs over Bluetooth.

When [`CONFIG_LOG_BACKEND_EPACKET_BT`](https://docs.dev.infuse-iot.com/latest/kconfig.html#CONFIG_LOG_BACKEND_EPACKET_BT)
is enabled, [Zephyr logging](https://docs.zephyrproject.org/latest/services/logging/index.html) output is made
available over a Bluetooth GATT link through [ePacket](https://docs.dev.infuse-iot.com/latest/embedded/app_features/epacket.html#epacket-api).

The infuse `bt_log` command initiates a Bluetooth connection to the requested device and subscribes to the appropriate GATT characteristic.
Once connected, the tool displays the log messages until the tool is terminated with <kbd value="meta">



</kbd>

 + <kbd value="C">



</kbd>

.

```bash
infuse bt_log --id 0x1234567890abcdef
```

## `--data` Also View TDFs

The `--data` flag can be provided to also subscribe to any TDF data transmitted by the device over the
[Bluetooth GATT peripheral](https://docs.dev.infuse-iot.com/latest/doxygen/html/group__epacket__interface__apis.html#ga1d2bd3e3b00ba06acef36f4cd9a05b51)
TDF logger backend.