How to make Brother HL 2040 printer working under Linux?

Go to this link -> https://www.openprinting.org/printer/Brother/Brother-HL-2040

Click on the link "directly download PPD" which is underlined in green colour

PPD for Brother-HL-2040

Now in your linux machine (Debian based)
goto printer settings -> Select the "provide PPD" option -> Browse to the downloaded PPD file and "apply"

Check with the test print.

How to install Samsung SCX-4521-NS multifunction printer in Linux?

Steps to install drivers for SAMSUNG SCX-4521-NS multifunction printer

1. Download the driver file for linux from the following url

http://www.samsung.com/in/support/model/SCX-4521NS/XIP-downloads?downloadName=DR

2. extract the downloaded file then open Applications → Terminal

Assume that the downloaded file is in the directory ~/Downloads

3. Issue the following commands as in the same order

$cd ~/Downloads/uld

$./ install.sh

give proper values (mostly yes/no options) whenever prompted

4. Once the driver got installed, connect your printer with the PC/Laptop then do the following steps

5. Go to Applications → System tools → Administration → Printing this will open printer configuration wizard.  (Am Using a debian derived distro named BOSS GNU/Linux, in your destro the "Printing" may be available under different menu item, with different name)

6. Click on Add button, give password whenever prompted. The connected printer will be automatically detected and then click on Forward button. Now a new popup window will open select the option “provide ppd file”

7. Now browse to the location of ppd file (which is /usr/share​/ppd/uld-samsung)

8. Now select the ppd file with the exact name as “Samsung_SCX-4650_4x21S_Series.ppd”

then proceed.

9. Now, test your configuration with “print test page”

How to configure TVS Dot matrix printer in BOSS

1. Click on System -> Administration -> Printing.  Give root password if prompted, a GUI application will open.
2. Click on Server -> Add -> printer.  If your dot matrix printer is connected with your system then it will be automatically get detected, then click on the printer name and click the forward button.
3.  Now you can see the driver for your printer model
if so select and forward else select the Epson-150 driver(it is very generic driver supports most of the dot-matrix printer.)

Note:
Once your printer configured successfully you can share your printers with others(who are connected with your computer with LAN cord) easily.  For that you need to enable the shared option by System -> Administration -> Printing -> right click on the printer icon -> properties -> Policies -> tick mark on the option "Shared"