CTI 2.0 is the predecessor of Freedom and is still used in classic environments and can be found occasionally in lightning setups.
This is a screenshot of the Interface:
In Salesforce classic it will be affixed to the top left of the Salesforce page, in Lightning it will be at the bottom (typically on the left) and will jump into view when call comes in and can be minimized when not needed.
For a full tutorial video please see below:
For a cheat sheet please follow this link:
Customisable options that may or may not be activated by your administrator:
- Availability states, quick case, record pause/resume, custom text field and picklists.