Digital Mode Text-To-Speech


   This article is for blind and vision-impaired amateur radio operators who want to hear spoken text from a digital modem program. It describes features in MultiPSK and TrueTTY that make text-to-speech operation possible.

   Four other modem programs with text-to-speech accessibility are described in separate articles:

   Accessible Digipan (Windows), cocoaModem (Mac OS X), MMTTY (Windows), and fldigi on a Windows XP system.

   Accessible Digipan, TrueTTY, MMTTY, and cocoaModem are accessible for screen reader users. MultiPSK and fldigi are not.

   The HamPod K3 Reader is a text-to-speech accessory for the Elecraft K3 and KX3 transceivers. As described in a separate article, the Reader can speak RTTY and PSK31 text that is decoded by a K3 without the use of a personal computer or screen reader software.


   MultiPSK freeware by F6CTE decodes a large number of ham digital modes. The registered version adds some Professional modes and other capabilities. MultiPSK has a long list of features, including integrated logging and automatic mode recognition & switching using Reed-Solomon codes.

     TrueTTY by UA9OSV works with a number of the most popular digital modes. There is a free version and a registered version that saves configuration settings. With fewer integrated features than MultiPSK, the user interface and documentation of TrueTTY are less complicated.

MultiPSK Text-to-Speech

   MultiPSK has two voice options for speaking decoded words:

          • the Microsoft voices built into Windows, and

          • the DigiTalk voice customized for hams by KH6TY.

   In addition, two modes can be spoken, one character at a time,
     using a MultiPSK English or French voice file:

          • JT65, a weak signal digital mode by K1JT, and

          • VOICE, a digital mode created by F6CTE for blind and
                         vision-impaired hams.

   JT65 and VOICE are error-correcting modes designed to work well in very low signal-to-noise conditions. VOICE is derived from an Olivia mode. In JT65 mode, MultiPSK opens a "Functions for blind or partially sighted Hams or SWL" subpanel for turning vocalization on/off, selecting the language, and displaying received text using a larger font.

   DigiTalk must be used with a modem program such as MultiPSK. The combination of DigiTalk plus MultiPSK works with versions of Windows that include Microsoft Windows Agent. Windows 7 users must install MSAgent via a Microsoft hotfix, and MSAgent is not available in later versions of Windows.

   MultiPSK has another very useful option—automated search for signals on the waterfall—which is described in the article on MultiPSK accessibility.

Text-to-Speech With TrueTTY

   TrueTTY does not have a built-in speech function, but it can be used with any screen reader software. Readers are not designed to work in a text window with streaming characters and scrolling lines, but TrueTTY can transfer decoded text to Windows Notepad, where a screen reader can be used. From the DXSoft website:

   "The menu command 'File / Open Buffer in Notepad' saves the visible part of the receiving buffer (about the last 20 KB) in a temporary file and opens this file by a text editor. Then you can view this file or print it. The hotkey of this command is CTRL-N."

   In 2008, W1BLS, reported in his blog (no longer available) that he used this feature of TrueTTY to operate with PSK31 and other digital modes. Details are in a separate article.

   A printed example of a QSO is here.

Text-to-Speech Quality

   The DigiTalk voice is an improvement over MicroSoft Windows voices because it spells out most call signs and Q signals. It is more convenient than typing keyboard shortcuts for a screen reader with TrueTTY.

   The tradeoff is an increased number of pronunciation errors, compared with a dedicated screen reader like JAWS. Digitalk author, KH6TY, commented, "Digitalk will translate 'hamspeak' fairly well—well enough to have a meaningful QSO, but will pronounce 'OK' as in 'Oklahoma'—nothing I can do about that except by incorporating a very powerful program..." Call signs may require clarification. For example, "Y" might be spoken as "E" and can be resolved by requesting the phonetic word (Yankee).

Sound Card Connections

   Two sound cards are used for digital mode text-to-speech—one for signal processing and one for the speech synthesizer.

   MultiPSK automatically makes the connections and lists them in sound card configuration menus on the Configuration screen. The card or chipset used by MultiPSK for signal processing is called the "Sound Card," and the card/chipset for optional speech synthesis is the "Auxiliary Sound Card." By default, the "Sound Card" is the one designated in Windows Sound Control Panel as the default recording device. The "Auxiliary Sound Card (to speaker)" menu choice in MultiPSK should always be the PC Speaker sound card, so spoken text is not transmitted on the band.

   In the TrueTTY "Input Sound Card" menu (Setup→Interface Tab) select the sound card for signal processing (eg, USB audio CODEC). Select the same card in the "Output Sound Card" menu. For screen reader output: In Windows Sound Control Panel select the computer's primary sound device as the default playback device (eg, Realtek High Definition Audio) so spoken text goes to the PC speaker.

For More Information

    MultiPSK accessibility
    TrueTTY accessibility
    PSK31 Operating Notes from a Blind Ham


   MultiPSK includes integrated text-to-speech options. The DigiTalk voice add-on is customized to spell most call signs and Q signals. With the weak signal (error-correcting) JT65 and VOICE modes, the characters are spoken one at a time. MultiPSK has an option to search for signals on the waterfall by pressing an arrow key.

   TrueTTY has a standard user interface that includes keyboard shortcuts. It can be used with any screen reader program.


   Thanks to F6CTE, for the accessibility features in MultiPSK and to KH6TY for developing DigiTalk. Thanks to W1BLS for his blog about TrueTTY for blind operators, and to KB1OLH for her comments on the blog. F6CTE, UA9OSV, and KH6TY, answered my questions. 3A2MW, recommended MultiPSK.


Author Information

   Peter DeNeef, AE7PD, is an Extra Class amateur radio operator in the U.S. This Web site has no ads or conflicts of interest.
Email:  HamRadioAndVision "at" gmail "dot" com.

rev. 5/26/2017

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