Configuring TrueTTY
for Blind and Vision-Impaired Hams
This article is for blind and vision-impaired amateur radio operators who want to use the TrueTTY digital mode program. Three special program features are related to vision:
For screen reader users,
• A keyboard shortcut to export received messages for a
screen reader.
• Adjustable AFC can automatically tune to a signal you
hear on the radio.
For sighted hams,
• Built-in high visibility text.
All digital mode programs have a large number of settings. For the purposes of this article, most of the settings in TrueTTY can be left unchanged. Initial program setup does require you or a sighted assistant to read directly from the computer display because the menu is not accessible to a screen reader.
The well-organized menus are described in the Program Overview in the Help Menu.
Configuring TrueTTY
To use the vision-related features of TrueTTY, the settings you need are grouped as follows:
• Information about the interface between your radio and
the computer.
• How do you want to tune the radio?
• Do you use high visibility text?
• The mode you plan to use most often (RTTY, PSK, etc).
• Manual transmit switching for screen reader users.
• TrueTTY macros you will use.
Most settings can be entered using the Setup Menu. In addition, a couple of changes to the TrueTTY.INI file make the program more accessible for screen reader users. The .INI file saves your menu settings and is enabled when you register the program. It is in the Windows ProgramData folder, which is hidden by default. A typical location is C:\ProgramData\TrueTTY\TrueTTY.INI. The file opens in a text editor, usually NotePad. Before editing, save a copy of the original (File → Save As) with a different name.
While you can change some parameters using the other menus and the Control bar near the top of the program window, those changes do not persist when the program is restarted.
Step 1: Setup Menu—Interface Tab
Data Exchange Port: Enter "None." This TrueTTY port is used for advanced applications such as External Modem Emulation (described in the Help Menu).
PTT Port Configuration: This entry depends on the type of Transmit/Receive switching you use. The options in the pull-down menu are described in "Connecting Sound Card With Transceiver" in the Help Menu. The author gives an example of a simple switching circuit. Or, if you use the radio VOX for switching, the PTT port type is "None." The settings for an external USB sound card interface are in the Appendix of this article. The WM2U web site has other examples of interfaces.
Step 2: Setup Menu—MOX Tab
It is convenient to have TrueTTY transmit automatically when you start typing and stop when all the text is sent. Configure this by clicking on the MOX Tab in the Setup Menu. MOX refers to manual transmit switching.
Select "TX at keyboard press" and "Rx at free buffer."
Step 3: Tuning
There are two basic ways to choose the operating frequency:
• View the spectrum or waterfall display and tune the TrueTTY audio frequency filter. This is the method most commonly used by sighted hams.
• Screen reader users can tune the radio VFO manually, and use a narrow radio bandwidth to help isolate the sound of one station. Listen to both the screen reader from the computer speaker and the audio from the radio speaker.
The following steps describe how to configure TrueTTY to tune automatically to the signal you hear on the radio:
i) By observing the TrueTTY spectrum or waterfall display, set the initial (on startup) program transmit and receive frequencies within the receiver bandwidth. For example, if the received audio frequencies extend from 1100 to 1800 Hz on the display, use the TrueTTY.INI file to set RxFrequency=1400 and TxFrequency=1400.
ii) AFC and TxAFC should be on by default. Confirm that AFC_On=1 and TxAfc=1 in the INI file.
iii) Local AFC Deviation, the maximum range in Hz that the AFC will deviate, is displayed on the far left of the Control bar. This is usually a small number chosen so the program will track a signal frequency that is drifting around slightly. If you increase the setting to cover more of the receiver bandwidth, the program will automatically tune to the digital signal you hear. For example, to increase the deviation to 150 Hz, divide it by 5 and enter the result in the INI file: AFC_Speed=30.
iv) Global AFC Deviation, the maximum deviation from the last frequency in use, is displayed just to the left of the AFC On/Off button in the Status Bar. Increase the limit in the INI file to the receiver bandwidth, eg AFC_Limit=700 for the example above.
Step 4: Setup Menu—Fonts and Colors
The Fonts and Colors Menu has a wide range of fonts, styles (eg, bold), sizes, font colors, and background colors. Click on the "Set" button for each of the 11 categories in the Menu. A preview box shows the result of your selections.
The "Save" button stores your selections in the .INI file, so they become the default fonts and colors that are displayed when the program is restarted.
Step 5: Mode
The operating mode can be changed using the Mode Menu, but it reverts to the default when the program is restarted. Use the INI file to change the default mode, eg Mode=0 for RTTY and Mode=1 for BPSK31.
Step 6: TrueTTY Macros
The rules for macros are described in the Macrosequences chapter of the Help Menu, and the editor is in the Edit Macros Menu. The default template for the F1 macro calls CQ. Enter your call sign in the F4 macro box, and it is inserted at the appropriate location [m4] in the F1 macro. As described in the article on using TrueTTY with a screen reader, the useful default F12 macro clears the Transmitted Text Box.
Summary
TrueTTY has features of special interest to blind and vision-impaired hams:
• Export received text for a screen reader.
• Tune automatically to a digital mode signal you hear.
• High visibility text.
Appendix: Using an External USB Sound Card
These are the TrueTTY settings I use for an external USB sound card interface, a MicroHam USB Interface III. Using the MicroHam software, PTT is assigned to a virtual serial port (eg, COM9):
PTT port type: COM-Port.
PTT port number: COM9.
Input sound card number: 0 Microphone (3-USB Audio Codec).
Output sound card number: 1 Speakers (3-USB Audio Codec).
Data exchange port: None.
All other settings=default values.
The radio CAT control port is not used by TrueTTY.
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. 1/29/2012
Related Articles: High Visibility Digital Mode Text
Digital Mode Text-to-Speech