How would I go about changing the serial baud rate on a TTY

[Doctorwho8]

Hello!
I followed these steps:
First I entered:
sudo systemctl enable serial-getty@ttyUSB0.service
And then I entered:
sudo systemctl start serial-getty@ttyUSB0.service

That was copied from:
http://0pointer.de/blog/projects/serial-console.html

Which provided the details as if I was working on an Intel system running Debian.

After entering the second command string on the serial console screen I immediately saw a prompt arrive on my second Putty terminal.That was running 9600 baud. I need to take this down to 4800 baud. Reason being is that it will be connected to a RS Model 102 who does 4800 rather well, but does 9600 baud poorly. I have vague memories of doing so sometime earlier on this Pi3B but, ah, it was so long ago I can not remember the steps. I found an earlier Forum series on a similar subject, and noted that the correspondent there faced a similar problem. But trying the recommended steps now wasn't at all working.

[topguy]

Normally you would just set the baudrate in the program that uses the serialport. If you are using a dedicated serial-library for your chosen language ( e.g. Pyserial ) those libraries will let you control the baudrate.

But if you just want to change it from the terminal the command is:

Code: Select all

stty -F /dev/ttyUSB0 4800

(of course use the correct device name for you.. )

.. but is this a usb2serial device connected to the USB port of the Pi ?
.. do you really want to have a login terminal for that ? ( i have no idea what an "RS Model 102" is )
.. what was the motivation for activating getty for that serial port ? ( if you wanted some output you could have just done "echo "Hello" > /dev/ttyUSB0" )


( And why on earth choose the eight Doctor ?? )

[Doctorwho8]

Normally you would just set the baudrate in the program that uses the serialport. If you are using a dedicated serial-library for your chosen language ( e.g. Pyserial ) those libraries will let you control the baudrate.

But if you just want to change it from the terminal the command is:

Code: Select all

stty -F /dev/ttyUSB0 4800

(of course use the correct device name for you.. )

.. but is this a usb2serial device connected to the USB port of the Pi ?
.. do you really want to have a login terminal for that ? ( i have no idea what an "RS Model 102" is )
.. what was the motivation for activating getty for that serial port ? ( if you wanted some output you could have just done "echo "Hello" > /dev/ttyUSB0" )


( And why on earth choose the eight Doctor ?? )

Hello!
First things last. I chose him because it seems that the reality that Doctor Who does his/her best in seems to be largely ignoring him. Never mind when he first surfaced, and then was last seen which was the movie celebrating the 50th anniversary of the Doctor. And next things next, please examine here first: https://arstechnica.com/information-tec ... model-100/ I did try it out on the original Pi and found that at the speed he set it for the screen on the Radio Shack Model 102 I used,, the screen smeared.

I also used the information here: https://zork.net/~octal/mod100.xhtml there was large amounts of information there. Finally several years ago for a completely different purpose I did manage to change the baud rate on the whole business. Back then I had connected to the same device a Pi3B I had connected to it, two Pi Zeros, one was working as a Gadget Zero Serial, and the other was working as a Gadget Zero Ethernet one. There's an unrelated issue of the WiFi departing in this configuration for the Pi3B when all of that there was connected this time.

Also here http://www.club100.org/ you should find out more information for the Radio Shack TRS-80 Model 102 for it.

[topguy]

This thread:
viewtopic.php?t=155807
.. should contain all you need. ( note answers by dgordon2 )

just ask if seomthing is unclear.