Devterm CM4 printer prints nothing but "bar codes"

DevTerm Firmware and Apps
1

Hi all. I finally got some paper for my devterm printer. Unfortunately, all it prints is the exact pattern of bars no matter what I try to print. I eventually tried

sudo apt install -y devterm-thermal-printer

after reading a forum post. This actually caused the printer to completely stop working and disabled the networking as well. I reimaged last time because I could not figure out why wifi stopped working and nothing seemed to fix it. This time I immediately tried:

sudo apt remove -y devterm-thermal-printer
sudo reboot

Network support came right back up. Now the printer canā€™t even print the bar code errors anymore. It does nothing at all because the driver is gone. I decided I donā€™t know what I am doing and I donā€™t even know if the printer is DOA out of the box. Sucks because this is one of the most fun things about this device.

I tried this command too when the printer made noises and spat out bar code:

echo -en ā€œ\x12\x54ā€ > /tmp/DEVTERM_PRINTER_IN

it spat out more bar codeā€¦just about a two inch long bar code of the exact same pattern as the thing does of I print ā€œtestā€ in text editor or geany. Same pattern, just shorter. I am using vonylist 58mm thermal paper as advertised it would print with.

Anyone have a clue what the issue might be?

1 Like
2

Thanks for reporting this issue just purchased the CM4 processor to use in my A06 DevTerm I use an external thermal printer now and have included my raw notes:

l_susb command displays all devicesā€¦

When I use an external USB thermal printer:

USB printers may present themselves to the system differently depending which USB- to-serial chip they use internally. Try the following first:

ls -l /dev/usb/lp0

If the response is something like:

crwxrwxr-x 1 root lp 180, 0 Mar 14 14:11 /dev/usb/lp0

Then this is a recent model. But if instead you get:
ls: cannot access ā€˜/dev/usb/lp0ā€™: No such file or directory

Then try:

ls -l /dev/ttyUSB0

Donā€™t fret if your USB printer is the ā€œolderā€ model. All of these print images equally

well. Just need to know which it is: /dev/usb/lp0 , or /dev/ttyUSB0 .
Letā€™s verify we can print something. For a current ā€œ lp0 ā€ model, type:

chmod 777 /dev/usb/lp1

echo -e ā€œThis is a test.\n\n\nā€ > /dev/usb/lp0

echo -e ā€œThis is a test.\n\n\nā€ > /dev/usb/lp1

prints plain test file

cat ā€œtestfinenameā€.txt > /dev/usb/lp1

wher ā€œtestfilenameā€ is the name of your plain text fileā€¦