etTextToSpeech Sample Program


This sample program shows how easy it is with TeleTools to add speech to your application.  Text-To-Speech (TTS), allows you to convert written text into spoken words.  

  • Save development time by doing your initial testing with text instead of having to record wave files

  • Create any wave format you need

  • Be able to speak dynamically changing information for which pre-recording wave files would be impossible or pasting together wave files using conventional methods with our etPlay would be too difficult.

  • Choose from many available voices and speech engines

Be sure to read our Speech Tutorial 

NOTE: You must download and install SAPI 5.1 from HERE.  XP users - XP comes with 5.0 of SAPI and does not include the Microsoft Mary and Mike voices. The LH voices do not work with the default engine. Go into the Speech section of the control panel and set your default voice to a Microsoft voice instead.

Click here for more information about SAPI Speech.

Using This Sample Program
Download this Sample Program 
How this Sample Program Works
Source Code
Release Notes

Development Environment Technical Information
Telephony Hardware Technical Information



  • Microsoft SAPI 5.1 SDK (available from Microsoft HERE)

  • TeleTools 3.7 or above

  • Telephony device with a wave audio driver

Using This Sample Program

This program demonstrates using Microsoft's SAPI 5.1 Speech SDK, along with TeleTools, to create an application that converts Text To Speech for use in Telephony applications. Useful applications of this technology include IVRs, voicemail and situations where a wave message cannot be pre-recorded or constructed reasonably by concatenating wave files using etPlay. In addition, this sample program demonstrates using XML tags in the text to control how the speech is sent, and responds to DTMF digits pressed on the telephone.

To make this program compile on your machine, be sure to have the etLine, etPlay and etRecord components on your form and to click the "AboutLoadSerialnumber" property to install your serial number into the components. Then click on the enabled property to set it to true. You must compile this program with a purchased serial number or it will operate with reminder screens.

You also need to have the Microsoft Speech SDK version 5.1 installed according to the instructions on our website.  We are using SpVoice, SpObjectToken and SpMMAudioOut functions from the SDK.

When the device selected in the ComboBoxDevice list is not active, you can scroll through the "audio output" devices to find your sound card and test speech without having to make a phone call. Choose a wave format from it's combobox, and a voice you would like to use from the Voice combobox and then use the play, stop and pause controls at the bottom of the form to control the spoken text.

Next, find your telephony device in the device list and check the "active" checkbox. You should see the device selected and activated in the "call progress" window. the Audio Output combobox will gray out since we automatically select the proper wave device that is associated with your telephony line device.

You must select the proper native wave file format for your device in the wave format combobox. A message box and entry in the log will notify you if the device cannot handle that format. For most devices, 8kHz16BitMono
will work, however, some devices only support another format or support more than one format. Dialogic cards, for example, will only support 11kHz8BitMono, which is a slightly better sampling rate. Hi-Phone's support 8kHz16BitMono, 11kHz8BitMono, and 11kHz16BitMono.

You may even be able to play other wave formats because of audio codecs installed on your machine. While this can be a nice feature, you must be careful because you cannot depend on that CODEC being installed on another
person's machine. In addition, it is much better to play in the native format of the device, using it's hardware and firmware to decode the wave file instead of depending on the computers resources to handle something as processor intensive as wave streams. This can lead to dropouts if the CPU gets busy or hardware interrupts interfere with the CODEC process.

Once you have the wave format selected and the device activated, you can place a number into the phone number window and click "Dial". All of the call progress events and helpful info about TeleTools methods and properties being accessed will appear in the call progress log window.

As soon as you answer the call (and for devices like Dialogic cards and Hi-Phones that give positive voice detection, say "hello"), you will see the "OnConnected" event trigger and the speech code run in this event handler will immediately start playing the text message typed into the speech text window. You can use the control buttons at the bottom of the window to pause, stop, re-start and play the message again. You can also press digits on your phone and watch the log and listen to the phone call to see and hear DTMF digit events processed
and messages played telling you which digit you pressed.

You may place incoming calls to the line attached to your device. You will see the "OnOffering" event fire signifying an incoming call, get ring events and CalerID events, and the hangup and Answer buttons will become active.
You can now click the Answer button to answer the call and the caller will immediately hear the greeting.

When you are finished with a call, hang up the phone or press the Hangup button. If the remote caller hangs up, we automatically issue the hangup command on your end.

We recommend that for learning, testing and debugging, you click on the "TeleScope" button to see how powerful a tool it is for viewing almost everything going on in your program. Please read the help file sections about
TeleScope, it may be the most valuable first advice we can provide to you. You may also place the line, "etLine1.TeleScopeActive = True" anywhere in your code where you want TeleScope to popup. It's a great idea to include a secret hotkey combination in your code to enable the TeleScope for your components so that you or your clients can email informative logs.

Place outgoing calls and watch what events and in which order they fire. Place incoming calls and watch the OnRing and CallerID events fire. Then all you have to do is place your code in the correct event handler. Not all devices behave exactly the same. A modem is different from a voice modem which is different from a true TAPI compliant device. Please see our article on our web page and in the help file titled, "Working With Modems" for examples of things you may need to consider when programming your application.

Some devices can handle multiple calls, so good programming practice suggests that you reference the call handle in your routines by using the line: etLine1.CallHandle = CallHandle. If you need explicit control of multiple calls you would create a global variable to reference the correct call where necessary.

In addition, some devices, and even different versions of devices from the same manufacturer may have issues related to speech and/or wave files. For example, some Dialogic cards must have a buffer setting change to minimize a stuttering effect that can happen when they can't process the wave data properly.

NOTE: We have written this program to show you some of the things TeleTools can do and to show many of our methods and properties. We have provided help on how you can implement speech using Microsoft SAPI yourself. We cannot support Microsoft products, but can provide consulting to help you with questions regarding your telephony projects if you need it.


Use the rate and volume sliders to see how it effects the spoken text and look over the source code to see which features can help you in your application. Type your own text in the text window and look over the XML tags shown inour sample to see how you can alter volume, rate, voice, pitch and more to have more control over how your application sounds to users.

Click on the Line Config button to see if your device supports this feature to call up it's TSP configuration screen. Likewise, click on the TeleScope button to see what is happening behind the scenes and to use other methods
and properties not written into this sample program. TeleScope allows you to take control over your device.


Read the Microsoft SAPI SDK help file to gain the most from Speech. You can implement Speech Recognition in the same way you implement TTS. View our web tutorial on Speech and follow the links to learn more about other speech engines you can use in addition to the free ones included by Microsoft. Some of the 3rd party speech engines, such as the one from AT&T sound like a real person.

Try our other sample EXE programs, available on our web site, and then download the sample source code if you want to find out how easy it is to use TeleTools to greatly simplify your telephony programming experience. We have other Speech sample programs that can give you more help if you need it. Use our "Premium Trial" to test our tools and gain the most from your evaluation. And remember to read the help section on using TeleScope and use it to learn, test, prototype and debug amost anything telephony related you are trying to do.


ExceleTel only provides the SAPI samples as a guide to to help our clients start the learning process to incorporate speech into their own applications. We cannot provide free support for Microsoft's SAPI, nor warranty that it will work in any particular application or with any particular hardware.

NOTE ABOUT VOLUME (especially Dialogic users)

Some devices have issues with volume.  In particular, Dialogic has a bug in their wave driver which does not report the volume level properly, it is always zero (0).  Therefore, making sure you put the following lines into your application will make sure to not save and reset a default volume which can wind up making your audio so low you can't hear it.  In addition, you may need to use the little trick below to set the volume if it gets set too low:

etPlay1.VolumeEnabled = True
etPlay1.VolumeDefault = False
etPlay1.VolumeReset = False
etPlay1.VolumePosition = 75

Then, in order to actually set the volume since you aren't using etPlay to play a wave file, but instead using SAPI to play text-to-speech, you must create a very small wave file containing silence. We've included one on this page for you to use. Then on a connected call, use the following code to send this wave file to your hardware to reset it's default volume:

etPlay1.SourceFileName = "10msof11kHzSilence.wav"
etPlay1.DeviceActive = True

Silence10ms11k8bitMono - 10ms of silence at 11kHz, 8-bit, Mono (Dialogic)
Silence10ms8k16bitMono - 10ms of silence at 8kHz, 16-bit, Mono (voicemodems)


Download this Sample Program

For Use TeleTools v3.7



EXE Ready to run!
Borland Delphi 5,6,7 Source code and wave files
Visual Basic 5,6 Source code and wave files
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How this Sample Program Works





The main TTS speech voice object, similar to etPlay.  It lets you select your voice, start and stop your speech and more.

SpObjectToken* Lets you get tokens representing object out of the registry.  Pointers to things like audio devices, speech engines, and voices are stored in the registry for ease of use in programming
SpMMAudioOut The speech SDK's wrapper for the Windows wave audio out functions
etPlay The ExceleTel etPlay wave play component
etRecord The ExceleTel etRecord  wave record component
etLine The ExceleTel etLine component for controlling TAPI telephony line devices
CheckBoxActive Activate and Deactivate the Telephony device
ComboBoxDevice Select the Telephony device
ButtonDial Dial an outbound call
EditPhoneNumber Enter the phone number to dial
ButtonHangup Hangup an active or disconnected call
ButtonAnswer Answer an incoming call
ComboBoxWaveDevice Select and change the Speech / Wave Audio Output device.  This is selected automatically if you select and activate a telephony device
ComboBoxWaveFormats Select and change the output wave format
ComboBoxVoices Select and change the speaking voice
TrackBarSpeechRate Adjust the text to speech rate
TrackBarVolume Adjust the volume of the spoken text
Memo1 Call progress status log window
MemoTextToSpeak Enter any text you wish to have spoken
ButtonClear Clear the call progress / speech progress log window
ButtonLineConfig Display the telephony device TSP configuration dialog (if implemented by the device manufacturer)
ButtonTeleScope Display the TeleTools TeleScope diagnostic, logging and debugging tool
ButtonStop Stop the text from speaking
ButtonPause Pause the speech
ButtonSpeak Use TTS to speak the text in the Text to Speek window or play it again
BitBtnInfo Display info about this sample program in an about box
LabelCallProgress Labels the Call progress log window
LabelTextToSpeak Labels the input window for text to speech
LabelRatePos Displays the selected / changed speech rate
LabelVolumePos Displays the selected / changed TTS volume
Panel1 Holds the speech and wave related controls

* Controls with an asterisk are true visual components in Delphi, but in other languages, they are calls to the SDK

Event Handler Routine









This sample uses only the event handlers that are part of the form and the components


Release Notes

First Release