[BRLTTY] Focus 1 70 display and USB to serial adapter: possible connecting this scenario?

Hammer Attila hammera at pickup.hu
Sun Dec 22 18:00:22 UTC 2024


Hi,


I tryed an another test to detailed see anybody what happens if I 
attaching usb to serial cable and the Focus 1 display.

I used following command:

sudo brltty -b fs -d /dev/ttyACM0 -l all -L brltty.log

I see an interesting information:

My USB serial port trying communicate the display with 57600 baud rate, 
8 data bits, 1 stop bit, parity mode is 4, flow control is 0x00.

Not 9600 baud the right speed if a braille display is attached a serial 
port (independent the dongle is a real serial cable and real serial port 
hardvare, or an usb to serial adapter or cable)?

What do you think or suggest?

Perhaps me need buying an another usb to serial dongle with absolute 
sure working (if my motherboard perhaps not have a serial pin cable 
connector), similar with cstrobel crosslink.net use he's Alva display?

cstrobel, what dongle you use (based with lsusb output)?


My motherboard name is following:

ASUS PRIME B550M-K

Tech Specs, with describe the internal serial connector (perhaps only 
the back cable need buying):

https://www.ldlc.com/en/product/PB00569529.html


Attila

2024. 12. 22. 14:24 keltezéssel, Hammer Attila írta:
>
> Hi Dave,
>
>
> I tryed with you wrote, but not worked unfortunatelly.
>
> In syslog I see now following error message, translate to english for 
> you in Ubuntu 20.04, BRLTTY 6.5:
>
> Dec 22 14:01:56 hammera-pc brltty[1410]: unable to connect to polkit: 
> g-io-error-quark (159) Error initializing authority: Could not 
> connect: No such file or directory (1)
>
> What file missing for BRLTTY and polkit related? When I used the my 
> Alva display with USB connection, I not see similar error messages.
>
> Another interesting error messages:
>
> Dec 22 14:01:59 hammera-pc brltty[3886]: can't isolate namespaces
>
> Dec 22 14:01:59 hammera-pc brltty[3886]: required capability not 
> granted: cap_sys_admin (for injecting input characters typed on a 
> braille device)
> Dec 22 14:01:59 hammera-pc brltty[3886]: required capability not 
> granted: cap_sys_tty_config (for playing alert tunes via the built-in 
> PC speaker)
> Dec 22 14:01:59 hammera-pc brltty[3886]: required capability not 
> granted: cap_mknod (for creating needed but missing special device files)
> Dec 22 14:01:59 hammera-pc dbus-daemon[3210]: [session uid=1000 
> pid=3210] Activating via systemd: service name='org.a11y.Bus' 
> unit='at-spi-dbus-bus.service' requested by ':1.154' (uid=1000 
> pid=3887 comm="/bin/brltty -b ba -s no -x a2 -N " label="unconfined")
> Dec 22 14:01:59 hammera-pc at-spi-bus-launcher[3901]: 
> dbus-daemon[3901]: Activating service name='org.a11y.atspi.Registry' 
> requested by ':1.0' (uid=1000 pid=3887 comm="/bin/brltty -b ba -s no 
> -x a2 -N " label="unconfined")
> Dec 22 14:01:59 hammera-pc brltty[3887]: Screen Driver: a2 [AtSpi2]
> Dec 22 14:01:59 hammera-pc brltty[3887]: Braille Driver: ba [BrlAPI] 
> Version:0.1, 2005
> Dec 22 14:01:59 hammera-pc brltty[3887]: Speech Driver: no [NoSpeech]
>
> Dec 22 14:01:59 hammera-pc brltty[3887]: ioctl[KDMKTONE] error 1: 
> Operation not permitted
>
>
> Me not have other ydea. USB to serial adapter connection is Ok, 
> /dev/ttyACM0 device correct existing, the /etc/brltty.conf file 
> correct setted fs driver parameter and the serial device line.
>
> My Asus B550 motherboard based the tech specs supports one serial port 
> connector, but not have back panel connector connected the motherboard.
>
> Perhaps me need trying buying a 9 pin serial connector cable to the 
> motherboard connector if not have better ydea.
>
> General 9 pin serial to serial cable an another machine the display 
> works correct the /dev/ttyS0 device, so the display is not bad and the 
> serial port in the display is not bad.
>
> Unfortunatelly the display USB port with usb cable is unusable the 
> BRLTTY 6.5 and higher version, because shows following error message 
> the log file:
>
> [brltty] USB URB status error 75: The value is too large for the 
> specified data type
> 2024-03-31 at 14:28:26.852 [brltty] USB: endpoint descriptor not found: 00
>
> Attila
> 2024. 12. 21. 20:55 keltezéssel, Dave Mielke írta:
>
>> [quoted lines by Hammer Attila on 2024/12/21 at 15:49 +0100]
>>
>>> so I buied a Genbird USB to serial 9 pin cable.
>> That should work.
>>
>>> Both Ubuntu 20.04 and Debian 12 are correct detected my usb to serial cable,
>>> and created correct the /dev/ttyACM0 device.
>>>
>>> In /etc/brltty.conf file I set braille driver related config key, and added
>>> following line into the config file:
>>>
>>> braille-device    serial:ttyACM0    # First serial device.
>> Yes, that's correct.
>>
>>> Because the display shows only the focus 70 related status message and not
>>> the actual braille output, I restarted BRLTTY with sudo brltty -d
>>> /dev/ttyACM0 and -D fs command,
>> -D (uppercase D) is the wrong option. It tells brltty where to find the drivers, and I think that's what your problem is. To tell brltty which braille driver to use, please specify the -b (lowercase b) option.
>>
>
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