CTI ( computer-telephony integration), or sometimes simply "computer telephony," is the use of computers to manage telephone calls. The term is used in describing the computerized services of call centers, such as those that direct your phone call to the right department at a business you're calling. It's also sometimes used to describe the ability to use your personal computer to initiate and manage phone calls (in which case you can think of your computer as your personal call center).

CTI applications provide the ability to do one or more of the following:

Authenticate callers. Using one of several standard methods, the telephone number of the caller can be screened against a database.
Recognize a voice, either for authentication or for message forwarding
Using live, recorded voice, or touch-tone entered input, determine how to process a call (for example, by forwarding it to the appropriate person or department)
Provide interactive voice response (IVR) to callers
Match the number of a caller with a customer record and display it for reference when talking to the caller
Manage voice or video conferences
Collect and display pending live calls or messages that have been left by callers
Receive fax messages and route them to appropriate fax machines
For outbound calling such as telemarketing, predial callers
Based on call input, initiate a smart agent application to provide help with the caller's request

The Advanced Intelligent Network (AIN) is a telephone service architecture that separates CTI services from call switching and will make it easier to add new services. The Windows Telephony Application Program Interface (TAPI) and Novell's TSAPI are programming interfaces intended to make it easier to create applications that enable telephone services on a personal computer or in a local area network.