B.B. Link Adapter
B.B. Link is the adapter that connects iPhones and iPads to Kenwood TH-D75 and TH-D74 radios. With it, iOS apps like RadioMail and Packet Commander can use the radio's built-in modem. Plug it into a USB-C power source, turn your radio on, and you are set.
Open source
B.B. Link lives on as an open source project. The firmware and the Configurator app source code are freely available, so you can build your own adapter, study how it works, or contribute improvements.
Frequently asked questions
Why is this adapter needed? +
In the TH-D74/5, Kenwood uses the Bluetooth Serial Port Profile (SPP) to expose the internal modem. Apple does not allow applications to use the Bluetooth SPP on iOS and only permits Bluetooth Low Energy (BLE). This combination results in a frustrating incompatibility.
Does it need to be plugged into the phone? +
No, the adapter only requires power from USB-C; all data exchange is done via Bluetooth. If your iPhone is from a generation earlier than the iPhone 15, it has a Lightning connector instead of USB-C. Using a Lightning-to-USB-C adapter does not enable the phone to function as a power delivery host and will not power the adapter. To use the adapter with an older iPhone lacking USB-C, you can use a portable power bank. Additionally, your vehicle may have a USB-C power plug, or you can use a USB-C car charger that plugs into the cigarette lighter.
What about Lightning connectors? +
Older generations of devices with a Lightning connector won't power accessories. Lightning-to-USB-C adapters will not provide power to a connected device; they only allow USB-C cables to be used for charging the phone. To use the adapter with a previous generation iPhone, you can use a USB-C portable power bank instead. Additionally, your vehicle may be equipped with a USB-C power plug, or you can use a USB-C car charger that plugs into the cigarette lighter.
Does it work with the TH-D74? +
Yes, the adapter works with the Kenwood TH-D74 and TH-D75 radios.
Does it work with Android or macOS? +
The Android and macOS operating systems allow applications to access the Bluetooth Serial Port Profile (SPP) and can pair natively with the radio, so no adapter is necessary in this case.
Does it work with other radios? +
The adapter is designed to work only with the Kenwood TH-D74 and TH-D75. To date, they are the only known radios that expose a modem via Bluetooth.
Why doesn't Kenwood or Apple fix this? +
¯\_(ツ)_/¯