Glossary of Braille display-related terms

About the glossary

Throughout BrailleDB, we refer to a lot of things about Braille displays. In case any of the terms are new to you, this page defines all the technical terms involved and provides some information about how they affect the experience of using the display. If you find something unclear, let us know and we can provide more information or improve the glossary.

Advance Buttons

Advance buttons are keys found at either end of the display to pan back and forth. Some displays have one button at either end, which is usually configurable so you can use whichever hand you prefer to advance the display. Other displays have two on either end, allowing you to perform both operations with either hand. Other options for advancing the display include thumb keys and touch control .

Arrow Keys

Arrow keys are dedicated keys for directional movement, often useful for navigating the interface of the internal functions or connected device. Displays without arrow keys accomplish the same thing with keyboard commands, for example dot1-chord and dot4-chord instead of up and down arrows.

Audio Reader

The ability to play audio files through speakers or headphones. The description will list supported formats and other information about how audio files are played. Note that this is independent of playing audio in Daisy books, for which the Daisy reader must also be available.

Availability

This indicates whether the device can be obtained now. The current options are:

• Available: The device is commercially available and can be purchased, new, from manufacturers or distributors.
• Discontinued: The device is no longer available from its manufacturer. Some distributors may still have units left, and there may be secondhand units available. A device being discontinued doesn't necessarily mean that the manufacturer no longer has spare parts or offers support, but they might not, so if this is important, it can be helpful to research the availability of those things or contact the manufacturer to find the answer.
• Rumored: The device has not been released yet. Information posted here may change before the device becomes commercially available, and it might not be available in the first place. The maintainers of the Braille Device Database will create pages for rumored devices only when there have been enough announcements of a product's release or intended specifications that they can be compared. If a device stops being developed, the rumored page will be removed from the database.

Battery Information

This field provides any information about the battery that is currently known. The degree of information varies widely between devices. When possible, the type and model number of battery will be provided, which is useful in finding suitable replacement batteries.

Many displays do not use standard batteries, in which case the type, voltage, and capacity will be listed if these are known. These do not always provide enough information to identify or construct replacements, but they are required to do so.

Battery User-replaceable

If the battery is user-replaceable, then it is possible with only minor tools to remove an old battery and insert a new one. This can be useful either if a battery goes bad and can be replaced without returning the device to service personnel or if you want to have spare batteries on hand. Please note that some displays with user-replaceable batteries do not make it easy to charge spare batteries and don't intend to operate that way.

Bluetooth Client

Bluetooth is a short-range wireless communication standard. The client connection is the connection where the device connects as a display, keyboard, or audio device to another device (the host). This information will also provide the version of Bluetooth. All versions of Bluetooth are backward-compatible, so an older Bluetooth client version than a computer or phone's version will not cause problems connecting them.

Bluetooth Host

Bluetooth is a short-range wireless communication standard. The host connection is the connection where the device connects to a peripheral such as a Bluetooth speaker or keyboard. If you are looking for the connection where the device connects as a Braille display over Bluetooth, see Bluetooth client .

Braille Editor

An internal application which can edit a Braille file. As compared with a text editor , the Braille version does not translate between print and Braille but instead shows Braille dots exactly as they are entered. On displays with both editors, it is common to use the Braille editor for files which don't automatically translate, such as Braille music, shorthand, or unsupported languages.

Braille Languages

For displays that can translate text files to Braille, this indicates the Braille tables available for this. This is only necessary for reading text files in the language's Braille code. If the file is already a Braille file, then there is no need to have the Braille language. Some displays do not support translating text files , so they do not have any Braille languages but can be used to read Braille files in any table which have been produced by software running on a computer. For the languages of the internal menus, see interface languages .

Braille Reader

An internal application for reading, but not editing, raw Braille files. Similar to the Braille editor , this is intended for Braille files which have already been translated. If you have a file which needs to be converted to Braille, then either the display must also have a text reader , or you must convert the file to Braille before transferring it to the device.

Calculator

An internal application for doing mathematical calculations. The description of the calculator will describe which operations it can perform, with the most basic type being the four-function calculator supporting only addition, subtraction, multiplication, and division. More advanced calculators support parentheses to combine calculations, exponentiation, trigonometric, logarithmic, variables, and other operations.

Calendar

An application allowing you to record appointments and see a schedule of them. Some calendar applications can sync this information with cloud accounts, while others are purely internal.

Cell Tessellation

Cell tessellation is one of the recognized types of graphics display in which dots on the display are only present in Braille cells with gaps between cells and lines where there are no dots for graphics. Graphical data can still be displayed, but lines passing over a cell or line boundary may be somewhat uneven even if the original line was perfectly straight. Because the typical separation between Braille cells is not an even multiple of the inter-dot distance, diagrams displayed on a cell tessellation display are not to scale as they would be on a full graphics display . Note also that displays with a large distance between lines will not be counted as a cell tessellation because horizontal gaps in the image would be so wide that they would make graphics interpretation difficult.

Cells

The total number of cells across all lines, if this is a multiline display.

Cells Per Line

The number of cells in a line. If this is a single-line display, this is the total number of cells.

Clock

A way to see the current time on the Braille display, whether or not it is connected to another device.

CPU

The CPU, central processing unit, is the main chip which runs the software on a display. The CPU is important to how quickly programs will run, though the quantity and speed of RAM and the specific software are also important factors.

Daisy Reader

Daisy (Digital Accessible Information System) is a format for books and other materials that contains navigation elements. Daisy materials can contain text, audio narration, or both, and Braille displays may support both or only text materials. For playing audio files outside Daisy, see audio reader .

Dot Corp Refresh

Dot Corp cells are one type of refresh mechanism , manufactured by Dot Corporation in South Korea. There have been three generations of the Dot Cell technology so far, with each generation having faster and quieter refresh. The cells on a display using Dot cells are covered with a thin plastic membrane which is necessary to keep the cells from getting blocked, but the cells are much more compact and thus they can be packed more tightly together. One limitation of Dot cells is that they do not refresh well while fingers are touching them, meaning that to properly refresh, the user's hands must move away from the area. Newer Dot cells will detect when the fingers move and refresh the area they were touching, whereas older generations will not refresh properly unless the display is clear. There is a table comparing refreshing mechanisms providing some differences between Dot cells and other common methods.

Dot Pitch

The Dot Pitch of a display refers to the distance between pins. Generally, this is most relevant for graphics displays . The dot pitch will be reported in millimeters, with a smaller number indicating that dots are more tightly packed together. Another way that this information can be reported is dot density or resolution which works in the opposite way, that is to say that it indicates the number of dots that fit in a certain area and a higher number indicates dots more tightly packed together. While these measurements are reporting the same information and can be converted, we report dot pitch because comparing paper Braille dot spacing to dot spacing on a graphics display tends to be easier that way.

Dots Per Cell

Many Braille codes use six-dot cells, but many Braille displays show eight dots in each cell. This lets dots 7 and 8 be used to display the cursor location, formatting, focus, or other information. Some have used this ability to develop eight-dot Braille formats which also use those dots for content. Some displays only support six dots per cell.

Editor Supports Other Formats

Whether the text editor supports formats other than plain text. The specific formats will be listed in the description of the editor. When supported, common formats include docx (the default format for files from Microsoft Word), odt (the default format for files from LibreOffice Writer), rtf (rich text format, an older format for documents which supports formatting information), and PDF (generally only text-based PDF files are supported). Note that some text editors support opening files in these formats but do not support saving files in these formats.

Feature Level

The feature level of a display describes how many things the display does when it is not connected to another device. This isn't a technical term, but it can be useful to filter displays into rough categories. The feature levels we have identified and used in BrailleDB, along with what each one means, are as follows, listed from fewest to most features:

• Simple display: The display can only be used as a terminal to another computer or phone. Most simple displays have a basic menu and a few have a clock when not connected to a computer, but no internal applications.
• Reader display: The device can be used without connection to another device, but only to read files. Depending on the display, it may only support reading files that have already been converted to Braille, or it may have onboard Braille translation (see text reader ). If you can also write files, the display counts as a smart display.
• Smart display: The device has some built-in applications, at least including a notepad or text editor allowing you to take notes, store, and retrieve them. Some displays in this category include some other applications as well. Consult the features section for more details.
• Notetaker: The device includes many tools that you would find on a computer, but you cannot install others unless they are specifically built for that device. Generally, if there is a web browser or an email client, a device is at least a notetaker. This term may sound confusing since you can take notes on a smart display. We use the term because it has historically been used to distinguish these devices from other displays. The concept of a smart display which wasn't a notetaker is relatively new compared to the others.
• Braille computer: The device runs an operating system where you can install applications compatible with that operating system and access them. Most modern computers in this area run either Windows or Android.

Full Graphics

Full graphics is one of the recognized types of graphics display in which dots on the display are of an equal distance apart. In a full graphics display, a line drawn across the display will look the same all the way through. While it may not be as straight or clear as a tactile graphic on a piece of paper, it will not be interrupted by cell boundaries as would be seen in a cell tessellation display. The clarity of an image displayed on a full graphics display depends on the dot pitch of the display.

Graphics

Some displays can display more than just text by showing a tactile representation of a graph, diagram, or picture. Generally, displays that can display graphics require more lines than a single-line display has, but not every multi-line display is graphics-capable. There are two recognized types of graphics-capable display. In full graphics displays, dots are equidistant, whereas in cell tessellation displays, dots are in the typical layout of Braille cells. Refer to the definitions for those types for more information.

Related terms: Dot Pitch

Headphones

Whether traditional wired headphones can be connected to listen to audio. Some devices may lack a headphone jack but support USB or Bluetooth audio devices.

Interface Languages

Interface languages are the languages for internal menus, applications, or functions. When connecting a display to another device, you don't need a display to have a certain interface language in order to read that language from the connected computer or phone, since the screen reader running on that device controls what language of Braille is sent. You also don't need an interface language to read a Braille file in any language. If you want to translate a text file to Braille, you should verify that the desired language is listed in Braille languages instead.

Internal Storage

The space for storing personal files on the device. Some displays with internal features provide storage for user files, while others require the use of a storage card for these.

Lines

The number of lines the display can show. Most displays, even now, display only one line of Braille. In recent years, some multiline displays have been commercially produced which can show up to ten lines. Devices without a Braille display show zero lines.

Magnetic Refresh

Magnetic cells are one type of refresh mechanism . These cells work by using small electromagnets to change the position of pins or moving parts with pins on them. There is a table comparing refreshing mechanisms providing some differences between magnetic cells and other common methods.

Microphone

The ability to record audio on the device, either for storage or for use in other programs.

Modifier Keys

Modifier keys are keys that can be held down to change the effect of a character. On a normal computer keyboard, for example, modifier keys include shift, control, and alt. Some Braille displays also have modifier keys which can be useful in emulating keystrokes or defining many custom commands.

More Clock Functions

Functions related to timekeeping that aren't simply displaying the time and date. Common options include stopwatch (counts upward to measure the time taken to do something) and timer (counts down to alert you when a defined time period has passed).

Motorized Refresh

Motorized cells are one type of refresh mechanism . These function by moving disks or other parts with dots on them so they form the desired Braille patterns. There is usually a louder sound as these parts are moved. There is a table comparing refreshing mechanisms providing some differences between motorized cells and other common methods.

Operating System

The operating system of a device controls what software can run on it. This is most important for Braille computers or notetakers , because it determines what software can be installed and run on them. Some devices in other categories will also have the operating system listed, but this does not mean that other software can be installed on them. Almost all devices have an operating system of some sort, but that does not necessarily mean that they can install applications. Check the feature level to check whether this is supported.

Orbit Refresh

Orbit cells, officially Orbit TrueBraille, are one type of refresh mechanism . These cells do not refresh all at once, but instead refresh from left to right. This means that the time for the display to refresh depends on how many of the dots on the display have changed. Generally, a complete refresh takes between 500 and 750 milliseconds. Most Orbit displays refresh groups of 20 cells simultaneously, meaning that a 40-cell or even multiline display takes as long to refresh as a 20-cell display. These displays are louder than the more typical piezoelectric cells, making a rapid clicking noise as they refresh. We have an audio sample of an Orbit Reader refreshing a few times. There is a table comparing refreshing mechanisms providing some differences between Orbit cells and other common methods.

Other Functions

This is where programs that are less common are listed. There are many things that only one or a few devices have which didn't justify their own field. You can try to search these devices using the free text search boxes at the bottom of the advanced search page, though not all specification sheets will describe these in the same terms. For example, searching "music" in the free text field will show you devices that have some music Braille functions, but you should read each device's specifications to get the context.

Perkins Keyboard

A Perkins keyboard is a nine-key keyboard with a key for each of the normal six dots, keys for dots 7 and 8 (which usually act as backspace and enter keys), and a space bar. This keyboard is named for the Perkins Brailler, which has used such a keyboard for many decades. Common variations of the Perkins keyboard include having two space bars instead of one, placing the space bars below the display while the rest of the keys are above it, or, especially on smaller displays, placing dots 7 and 8 near the space bar to be pressed by the thumbs rather than on the edges to be pressed by the pinky.

piezoelectric cells

Piezoelectric cells are one type of refresh mechanism . Piezoelectric cells have been the most common technology for Braille cells for decades and are still the most common mechanism in displays today. Compared to many other mechanisms, piezoelectric cells are faster to refresh but more expensive. These cells work by using the piezoelectric effect where crystals change shape when an electrical current is applied to them, moving small levers to move pins up and down. There is a table comparing refreshing mechanisms providing some differences between Orbit cells and other common methods.

Pneumatic Refresh

Pneumatic cells are one type of refresh mechanism . These cells work by using air pressure to lift the desired pins. Currently, this requires an air compressor which makes the device less portable and makes some background noise, although a more constant noise, and thus one that's easier to ignore or filter out, than other louder refresh systems. There is a table comparing refreshing mechanisms providing some differences between pneumatic cells and other common methods.

Price

The price to purchase one of these displays, new, from its manufacturer or from a distributor who uses the manufacturer-recommended price. If a device is no longer sold new, no price will be listed, as secondhand prices frequently change and depend on the condition of the device. Prices in this database are reported in U.S. dollars and generally represent the price from the manufacturer or a direct distributor which sells in the United States. Prices in other countries may not be equal. In the event that no U.S. distributor could be found or they didn't post the price, prices in other currencies have been converted. Prices don't include taxes. Promotions will probably not be reflected. This is a good way to compare prices in general, but it is worth checking prices of units you are interested in directly with manufacturers or distributors. If you have an idea about how this could be improved, we encourage you to contact the developers and let us know.

Power from USB

Whether the battery of this device, or the device during operation if it doesn't have a battery, can be powered from a USB connection. Devices without this require a separate power adapter. Note that some devices are powered over USB but require more power than most computers generally provide. A device that receives power over USB can be charged with any cable and charger that provides the required power, whether or not it was provided by the manufacturer.

Power Supply

Describes the cable necessary to charge or power the display. It is common for devices to be powered over USB , but when a device requires something else, as much detail as possible about the cable will be provided. If USB power is not used, then ideally, the manufacturer's cable is the best way to power the display. If a manufacturer's cable is not available, for example because the display is no longer manufactured or supported, then the information about the cable can be used to find or make a replacement cable. When doing this, the output voltage and polarity of the cables must match exactly, and the output current must be equal to or higher than the one from the original adapter.

QWERTY Keyboard

The QWERTY keyboard is the typical computer keyboard as found on laptops and desktops. This keyboard is intended for typing text characters rather than Braille, although some displays with QWERTY keyboards simulate a Braille keyboard by pressing letter keys on the home row. These keyboards come in a variety of forms, with most keyboards on Braille displays being similar to laptop keyboards in size, key spacing, and key feel.

There are two common layouts for QWERTY keyboards, ANSI and ISO. ANSI keyboards are commonly found in the Americas, Africa, Asia, and Australia and are distinguished by a long left shift key and a horizontal enter key. ISO keyboards are commonly found in Europe and are distinguished by a tall enter key and a punctuation key (writing the | symbol in English) to the left of the Z key. It is rare for a display to offer both format options. The format will be specified whenever possible on the device details page.

Note that, although this keyboard is labeled QWERTY, this doesn't mean it is limited to that character layout. Variants common in other languages, such as AZERTY for French or QWERTZ for German are often available, and in some cases so are other versions like Dvorak.

RAM

Random access memory, RAM, is temporary storage used to store programs and data when you are working with it. RAM is one of the factors determining the speed of a computer in normal operation. More RAM is not necessarily always better, as after you have enough for all the things you intend to do simultaneously, more will not make things any faster.

Refreshing Mechanism

Braille displays all move pins to display dots, but they have various ways of doing this. The different technologies have different characteristics, including cost, speed, noise, and sensitivity. The most typical mechanism is piezoelectric cells , but there are several other options, including Dot Corp's , Orbit , motorized , magnetic , and pneumatic . The definitions for each method provide more details about how each of these work, but a short comparison table between these types provides many of the relevant differences.

Routing Buttons

Routing buttons are buttons above or below each Braille cell. On displays that have them, these are used to put the cursor at the position of the cell or activate a control at the cell. This makes navigation faster since these buttons are close to the reading position and moving the cursor would otherwise involve moving by character, word, or line until it is in the desired location.

Simultaneous Bluetooth Connections

The number of Bluetooth connections that you can have activated at one time. Some devices only support one connection over Bluetooth, meaning that, to connect them to a different one, you have to disconnect them from the previously used device. Other displays support a certain number of simultaneous connections, allowing you to switch between multiple devices without disconnecting any of them.

Size

The size of a display is reported as length (left to right distance), depth (front to back), and height (bottom to top).

Text Editor

An internal application which can edit a text file and display it in a supported Braille table. As compared with a Braille editor , the text version translates between print and Braille automatically. This means that a text file, not previously translated to Braille, can be displayed in contracted Braille or any other supported table and that typed Braille can be read on a computer or by a sighted person without needing to translate it with other software.

Text Reader

An internal application for reading, but not editing, text files. Similar to the text editor , this application can translate text content into a supported Braille code without needing external software to do so.

Thumb Keys

Thunb keys are keys on the front edge of the display which can be pressed by the thumbs while the other fingers are reading on the display. These keys are nearly always used for navigation, either by panning the display or jumping by larger elements. Other options for advancing the display include advance buttons and touch control .

Touch Control

Touch control is technology to detect the position of the fingers while reading. This is not common and generally only available on more expensive displays. When present, the most common use is to refresh the display automatically when the fingers are approaching the end, but more complex touch-based commands are often also available. Other options for advancing the display include advance buttons and thumb keys .

USB Client

USB client ports are used to connect the device to a computer to act as a Braille display, transfer data, or the like. There have been many shapes of USB client ports, including USB-B, Mini USB, Micro USB, and USB-C.

USB Host

USB host ports allow you to connect USB devices like storage drives or keyboards. These are usually USB-A ports, which are more commonly found on devices, or USB-C ports, which are more modern. There are adapters allowing you to connect something with one port to a device that only has the other port.

Weight

How heavy the display is. We generally report the weight of the display alone, not including cases, power adapters, or other accessories.

WiFi

WiFi is the most common way to connect to the internet without plugging in a cable. Displays supporting WiFi can access the internet without another computer or phone. What you can do with this connection depends on the software features of the device. WiFi comes in a few versions, most of which interoperate with one another so you do not need to match versions exactly. The most important factor is that some WiFi networks operate on the 5 GHz frequency band, and devices with WiFi 4 or earlier cannot connect to these networks.