We have found that there are issues when connecting to CT007 series detectors using some phones running Android 7. This seems to be caused by an incompatibility between the way Android 7 handles Bluetooth versions and our firmware's Bluetooth stack, which creates issues during service discovery. The latest release of GammaGuard (4.4.11) aims to address this issue. To get the full benefit of this update, your CT007 detector's firmware should be updated. The procedure to do so is as follows.
If possible, use an Android phone not running Android 7 to perform the firmware update. Android versions 4.3, 5, 6, and 8+ should all work better. If that's not possible, an Android 7 phone can perform the update as well, but it may take several connection attempts before a successful connection is made.
- Install the latest release of GammaGuard (4.4.11)
- Power on the CT007 detector and start GammaGuard.
- From the main GammaGuard menu (top left icon, or drag in from left of screen), go to 'Settings' under 'External'.
- When prompted for a password, enter the default '1234'.
- Scroll down to the 'Automatic Firmware Updates' setting, and enable it. (Second last setting in the list.)
- Make sure that the 'Clear Bluetooth Cache' setting is DISABLED. (That is the default setting, unless you previously changed it.)
- Go to 'External Detector', and connect to your detector. As noted above, this may take several connection attempts before successfully connecting.
- Once connected, the firmware update should start automatically.
- Let the update finish and you will be automatically connected once it is done.
Note that if for any reason the update fails or is interrupted, it can be restarted and resumed as many times as necessary, with no risk of permanently bricking your detector. Even if you need to resume later from another phone. All you will need to do is choose your device type from a list (for example, a CT007-F would choose a device type of 'F') when prompted, then enter the serial number from your label.
Once the firmware is updated, connections to Android 7 devices should go better. Once the CT007 detector has been connected to a particular phone, the connection parameters are cached and subsequent connections are much quicker.
After your Firmware is updated, you may want to disable the 'Automatic Firmware Updates' setting again. This also speeds up connection and it prevents GammaGuard from starting Firmware updates at inopportune times.