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Configuration (OS agnostic)
Install Asterisk
First it is needed to install Asterisk. In most distributions, this should be easy because Asterisk is packaged with your distro. So use your distribution package manager to install. This howto is not made to focus on installation step.
Install HW drivers
You have to be sure that drivers for your ISDN PRI card are working. Simplest way is probably to install zaptel drivers (or it is together with your Asterisk package from your distro).
Ensure that hardware is working
If your hardware is working, you should be able to do