OpenVMS RTL DECtalk (DTK$) Manual

This manual serves as a comprehensive guide for system and applications programmers using the VMS operating system, detailing the DECtalk support routines found within the DTK$ facility of the Run-Time Library. These routines are specifically designed to interface with Digital Equipment Corporation's DECtalk device, which converts alphanumeric text into human-quality speech via its internal speaker, external audio system, or telephone.

The document covers a wide range of functionalities provided by the DTK$ facility, including:

• Initialization and Termination: Routines like DTK$INITIALIZE to set up the DECtalk device and DTK$TERMINATE to deallocate its resources.
• Environment Control: Setting various operating modes for text processing (DTK$SET_MODE), toggling speech on and off (DTK$SET_SPEECH_MODE), and adjusting voice characteristics such as type, speech rate, and pause lengths (DTK$SET_VOICE).
• Terminal Interaction: Controlling information displayed on a connected local terminal (DTK$SET_LOGGING_MODE) and managing terminal attributes (DTK$SET_TERMINAL_MODE).
• Speech Generation: Functions to speak text from a string (DTK$SPEAK_TEXT), a file (DTK$SPEAK_FILE), or phonemic representations (DTK$SPEAK_PHONEMIC_TEXT), as well as spelling out text letter by letter (DTK$SPELL_TEXT), with options for immediate return or waiting for completion.
• Index Management: Inserting and retrieving speech progress markers (DTK$SET_INDEX, DTK$RETURN_LAST_INDEX) for program synchronization.
• Dictionary Management: Loading custom word pronunciations into a supplemental dictionary (DTK$LOAD_DICTIONARY).
• Telephone Functions: Routines for answering (DTK$ANSWER_PHONE), dialing (DTK$DIAL_PHONE), hanging up (DTK$HANGUP_PHONE), and recognizing keypad input (DTK$SET_KEYPAD_MODE, DTK$READ_KEYSTROKE, DTK$READ_STRING).
• Hardware Status: Checking for DECtalk hardware malfunctions (DTK$CHECK_HDWR_STATUS).

The manual emphasizes that the DTK$ facility provides its own exit handler for clean termination, and users should avoid calling DTK$ routines within their own exit handlers. This edition, published in May 1993, supersedes Version 5.5 and supports OpenVMS AXP Version 1.5 and OpenVMS VAX Version 6.0.