For the generic CTI integration, you’ll need to know what your telephony system can and has to post to Zammad. You can find more information on that topic here:
Apart from the URL above (which your telephony system needs to know to push those information to it) you don’t need any further settings on that page.
“Entrant” is the block list which might be a poor translation in your language.
You can provide phone numbers you want to block / ignore - if your telephony system supports that, Zammad will return “action: rejected” and your phone system will hang up on the caller.
“Sortant” is the agent to extension mapping.
It allows Zammad to know which agent picked up and to display a new ticket dialogue when picking up.