[BRLTTY] Bluetooth connection problem

[Lars Bjørndal]

Hi, Mario!

You wrote:

> lars at lamasti.net (Lars Bjørndal) writes:
> 
> > On one of my rpis, I have recurring connection problems. The connection can
> > work for hours or even days, but suddenly, the connection stops working.
> > Typically, the reconnection after a braille display sleep won't work. A
> > system reboot doesn't solve the problem.
> >
> > In bluetoothctl, I get the following from info <addr>:
> >
> > (Please note the Name field. Shouldn't that have been Handy Tech Active
> > Braille ...
> >
> > Device 00:07:80:41:1E:B7
> >         Name: WT12-A
> >         Alias: WT12-A
> >         Paired: yes
> >         Trusted: yes
> >         Blocked: no
> >         Connected: no
> >         LegacyPairing: no
> >         UUID: Serial Port       (00001101-0000-1000-8000-00805f9b34fb)
> >         UUID: Human Interface Device... (00001124-0000-1000-8000-00805f9b34fb)
> >         UUID: PnP Information    (00001200-0000-1000-8000-00805f9b34fb)
> >         Modalias: bluetooth:v0047pF000d0410
> 
> That looks like a hardware bug.  If you haven't accidentally checked the
> wrong Bluetooth address, the device name should indeed be something
> else.  Do you specify the bluetooth address in your brltty
> configuration, or do you rely on the ability of BRLTTY 5.5 to find the
> device on its own?  If so, that will fail, since BRLTTY doesn't know
> anything about the "WT12-A" bluetooth friendly name.  You could try to
> go back to specifying the bluetooth address directly, maybe BRLTTY is
> still able to connect to the wrongly named device.

I've used the btr address in the BRLTTY config.

I tried on another host. On that host,, while scanning, I got NEW
device <address> Active Braille abb.... Below that wos some lines
saying Name and Aliase, both with the uncorrect name.

> > Doing connect 00:07:80:41:1E:B7
> >                 Attempting to connect to 00:07:80:41:1E:B7
> >                 Failed to connect: org.bluez.Error.Failed
> >
> > To fix the problem, I have to remove the device, and then re-pair it.
> 
> After re-discovery, is the device name correct, or does it still show up
> as WT12-A?

It's the same WT12-A on that host.

> I sometimes have a similar problem with the Active Star, however, when
> that happens, I usually am missing the Human Interface Device UUID and
> therefore have no working keyboard input.  Re-discovering seems to be
> the only thing that helps in that situation.
> 
> > Any ideas in how to fix this problem?
> 
> Contact Handy Tech.  This does not look like a software problem on the
> host.  It looks like a confused bluetooth stack on the side of the
> Braille display.  WT12-A seems to be the original name of the hardware
> they are using in the Active Braille.  At least that is what a quick
> google search suggests.  The host should never see the un-rebranded
> bluetooth name, if it does, it looks like a bug on the side of the
> display.  Felix, what do you think?

Yes, let's see what Felix comes up with.

Thanks and regards, Lars