An acronym for Wireless Telephony Application Interface. The WTAI specification describes standard telephony-specific extensions to WAE, including WML and WMLScript interfaces to such items as call control features, address book and phonebook services. WTAI was devised by the WAP Forum, and is not universally supported, although the Phone.com's UP.Browser supports WTAI.

Wireless Telephony Application Interface: This specifies how WAP applications can access mobile-phone functionality.

Wireless Telephony Applications Interface