IP Office provides Computer Telephony Integration (CTI) capabilities via the Telephony API. TAPI is a Microsoft interface that enables Windows machines to apply first- and third-party call control. DevLink complements TAPI by providing a real-time event stream containing information about telephone and trunk activity.

TAPILink Lite provides first-party CTI support for TAPI 2.1 and 3.0, enabling client applications to control one telephone line per PC. TAPILink Lite enables basic CTI, including answer, hang up, make call and transfer, and provides CLI/ANI for screen-popping. TAPILink Lite does not require license keys for use.

TAPILink Pro provides first and third party TAPI control of telephony devices. In addition to the functionality provided by TAPILink Lite, it also adds the ability to receive information on ACD queues, hunt groups, and provides additional advanced functionality. TAPILink Pro requires a CTI Link Pro license for each server configured to run the IP Office TAPI software.

DevLink Pro provides a programming interface that complements the Microsoft TAPI interfaces provided by TAPILink Lite and TAPILink Pro. This component provides a real-time event stream containing information on telephone and trunk activities. The Real-time event stream is enabled by installing the CTI Link Pro license key onto the system unit.

TAPI WAV driver provides software-based support for voice processing. The TAPI WAV driver is for use with TAPI 2.1 applications only; for TAPI 3.0 applications, IP Office supports the Media Service Provider (MSP) interface defined in TAPI 3.0. This functionality requires CTI Link Pro and TAPI WAV User licenses. Each license enables 4 ports of voice processing. TAPI WAV is no longer recommended for new designs and is not supported on 64-bit operating systems or on the Linux-based components of IP Office Server Edition.