Overview

This document describes the new DoubleTalk SSIL driver for Windows. The
driver consists of two files, DUBLTALK.DLL and SSIL.INI. These files are all
that are required to support the RC Systems DoubleTalk PC, DoubleTalk LT, and
the MicroTalk LiteTalk synthesizers.


Wave Driver Friendly

The support routines for the DoubleTalk LT and LiteTalk have been rewritten
to properly handle concurrent wave file playback and text-to-speech through
these synthesizers. Version 1.1 (or later) of the DoubleTalk wave driver must
be used in order for the SSIL to work properly in this regard.


Driver Setup

The only setup required in the SSIL driver is to specify which port the
synthesizer is connected to. The Port entry in the [SSIL] section of the
SSIL.INI file is used for this purpose. Valid entries are com1 thru com4,
and internal. For example,

[SSIL]
Device=DoubleTalk
Port=com1

configures the driver for DoubleTalk LT or LiteTalk connected to com port 1
(port parameters, such as baud rate and handshake protocol, are set
internally in the driver, and therefore are not required in the .INI file).
Port=internal indicates a DoubleTalk PC is being used. If the Port entry is
left blank (or is missing altogether), "internal" is assumed by default.


New Voice Controls

Three of the previously unsupported SSIL voice control parameters have been
"borrowed," to support unique DoubleTalk features. The old (original)
functions, new functions, and corresponding SSIL parameter selectors are
listed in the table below.

  Selector     Old Function         New Function
  --------     ------------         ------------
     a         Aspiration Gain      Articulation Level
     f         Frication Gain       Reverb Level
     x         Voiced Gain          Tone Level


Each voice control has been properly defined in the SSIL.INI file.

Five presets have been defined in the presets section of the SSIL.INI file.
These directly correlate with DoubleTalk's five voices, in name and voice
parameter settings. Note, however, that if your application controls the
synthesizer's individual voice parameters (such as pitch and tone), that it
will be changing part of the voice's basic characteristics.


Dictionary Support

The driver supports DoubleTalk exception dictionaries, which enables the
user to change the way any string of characters is pronounced, including
defining the pronunciation rules for a foreign language. The entry

Dictionary=

in the [DoubleTalk] section defines what dictionary file, if any, should be
loaded into DoubleTalk when the driver is opened. The file must have been
compiled as an "auto-load" (.EXA) dictionary. For example,

[DoubleTalk]
Dictionary=spanish.exa

will cause the Spanish dictionary, SPANISH.EXA, to be loaded into DoubleTalk.
Full pathnames can be used, as long as the total length does not exceed 64
characters.

The Language entries in the SSIL.INI file have also been predefined for the
English and Spanish languages. However, switching to Spanish will have no
effect if SPANISH.EXA is not defined in the Dictionary entry.
