Select the TAPI device driver for incoming and outgoing calls from the list box. See details for TAPI - Where do I find the TAPI driver?

 

With the button a window can be opened where all functions supported by the TAPI driver will be shown.

 

With the driver <Telephone Simulator> ESI CTI Connector for Salesforce can be tested with a phone simulator if no TAPI enabled phone is available.

See also
Where do I find this screen?
System Requirements- TAPI driver
Where do I find the TAPI driver?