Uncovering the Mystery: Why Bluetooth LE Scan Returns Address XX:XX:XX:XX:55:66 in Android 14

Are you tired of seeing the mysterious address XX:XX:XX:XX:55:66 pop up in your Android 14 Bluetooth LE scans? You’re not alone! Many developers have been scratching their heads, trying to understand why this strange address keeps appearing. In this article, we’ll dive deep into the world of Bluetooth Low Energy and explore the reasons behind this enigmatic phenomenon.

What is Bluetooth Low Energy (BLE)?

Before we dive into the mystery, let’s take a step back and understand what Bluetooth Low Energy is. BLE is a wireless personal area network technology designed for low-power consumption and low-cost devices. It’s a subset of the Bluetooth specification, allowing devices to communicate with each other while consuming minimal power. BLE is commonly used in IoT devices, wearables, and smart home devices.

The Bluetooth LE Scan Process

In Android, the Bluetooth LE scan process involves the following steps:

1. The Android device activates its Bluetooth adapter and starts scanning for nearby BLE devices.
2. The BLE devices in range respond with their advertising data, which includes their device name, device address, and other information.
3. The Android device receives the advertising data and stores it in a callback.
4. The callback is invoked, and the app can then parse the received data.

The Mysterious Address XX:XX:XX:XX:55:66

So, why does the address XX:XX:XX:XX:55:66 keep popping up in your Bluetooth LE scans? To understand this, we need to dive into the world of BLE device addresses.

Device Addresses in BLE

In BLE, each device has a unique 48-bit device address, which is typically represented as a 12-digit hexadecimal string (e.g., 01:23:45:67:89:AB). This address is used to identify devices during the scanning process.

Public and Random Device Addresses

BLE devices can have two types of addresses: public and random. Public addresses are unique to each device and are usually programmed during manufacturing. Random addresses, on the other hand, are generated randomly and can change periodically. Random addresses are used to protect the device’s identity and prevent tracking.

The Address XX:XX:XX:XX:55:66

Now, let’s get back to the mysterious address XX:XX:XX:XX:55:66. This address is not a real device address, but rather a reserved address used by Android for a specific purpose.

When an Android device scans for BLE devices, it also scans for a specific type of device called a “dummy device.” Dummy devices are used as placeholders to help the Android device manage its BLE connections. The address XX:XX:XX:XX:55:66 is assigned to these dummy devices.

Why Does Android Use Dummy Devices?

Android uses dummy devices to optimize the BLE scanning process. When an Android device scans for BLE devices, it needs to maintain a list of devices it has already discovered. To avoid duplicates and optimize memory usage, Android creates dummy devices as placeholders. These dummy devices are assigned the address XX:XX:XX:XX:55:66.

How to Handle the Address XX:XX:XX:XX:55:66 in Your App

Now that you know the reason behind the mysterious address, it’s essential to handle it correctly in your app. Here are some tips:

• Filter out the address XX:XX:XX:XX:55:66 in your app’s scan results. You can do this by checking the device address in the scan callback and ignoring any devices with this address.

• Implement a device filtering mechanism to ignore dummy devices. You can use the device name, device type, or other characteristics to filter out unwanted devices.

• Use the BluetoothAdapter.startLeScan() method with a filter to specify the types of devices you want to discover. This can help reduce the number of dummy devices in your scan results.

// Example code to filter out dummy devices
private BluetoothAdapter.LeScanCallback mLeScanCallback = 
    new BluetoothAdapter.LeScanCallback() {
    @Override
    public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
        // Check if the device address is XX:XX:XX:XX:55:66
        if (device.getAddress().equals("XX:XX:XX:XX:55:66")) {
            return;
        }
        
        // Process the device data
        processDeviceData(device, rssi, scanRecord);
    }
};

Conclusion

In this article, we’ve explored the mysterious address XX:XX:XX:XX:55:66 that appears in Android 14 Bluetooth LE scans. We’ve discovered that this address is assigned to dummy devices used by Android to optimize the BLE scanning process. By understanding the reason behind this address and implementing the necessary filtering mechanisms, you can ensure that your app provides accurate and reliable BLE device discovery.

Additional Resources

For further reading and reference, here are some additional resources:

• Android Developer Documentation: BluetoothAdapter

• Bluetooth Special Interest Group (SIG): Assigned Numbers

• Android Open Source Project (AOSP): BluetoothAdapter.java

Address Type	Description
Public Address	Unique to each device, programmed during manufacturing
Random Address	Generated randomly, can change periodically, used for device privacy
Dummy Device Address	Reserved address (XX:XX:XX:XX:55:66) used by Android for dummy devices

FAQs

Got more questions? Here are some frequently asked questions:

• Q: Why does the address XX:XX:XX:XX:55:66 appear in my BLE scan results?

  A: This address is assigned to dummy devices used by Android to optimize the BLE scanning process.

• Q: How can I filter out dummy devices in my app?

  A: You can filter out dummy devices by checking the device address in the scan callback and ignoring any devices with the address XX:XX:XX:XX:55:66.

• Q: Can I use the address XX:XX:XX:XX:55:66 for my own device?

  A: No, this address is reserved by Android for dummy devices. Using it for your own device may cause conflicts and issues.

We hope this article has helped you understand the mysterious address XX:XX:XX:XX:55:66 and provided you with the necessary knowledge to handle it correctly in your Android app.

Frequently Asked Question

Get the inside scoop on why Bluetooth LE scan returns a mysterious address XX:XX:XX:XX:55:66 in Android 14!