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A double-byte character is a character value represented by two bytes in a particular double-byte character set (DBCS). A DBCS can also use single-byte values, so the term does not mean every character in a text string occupies two bytes. The code page or encoding determines how to interpret the bytes.
What is a double-byte character?
In computing, “double-byte character” refers to a character encoded using a two-byte value in a DBCS. Microsoft describes a DBCS as an extended single-byte character set implemented as a code page. Such a code page can assign single-byte values to some characters, including English letters and digits, and double-byte values to others, including many Chinese ideographs and Japanese kanji. Microsoft’s code-page documentation explains this distinction.
In a multibyte character set, a character may consist of one or two bytes. When it uses two, the first is called a lead byte and the second a trail byte. Which byte values serve those roles depends on the specific encoding; the sequence must be read using the matching code page. Microsoft’s documentation on multibyte character sets describes the lead-byte and trail-byte model.
Does every character in a DBCS take two bytes?
No. “Double-byte” describes one kind of value supported by the character set, not a fixed length for every character in a string. A DBCS can mix single-byte and double-byte characters. You cannot reliably determine a character’s meaning from a byte in isolation: its position and the applicable encoding matter, especially when a byte can be part of a lead-and-trail pair.
#1 Best Overall
- KEYBOARD: The keyboard works for Windows with hot keys that enable easy access to Media, My Computer, Mute, Volume up/down, and Calculator
- EASY SETUP: Experience simple installation with the USB wired connection
- VERSATILE COMPATIBILITY: This keyboard is designed to work with multiple Windows versions, including Vista, 7, 8, 10 offering broad compatibility across devices.
- SLEEK DESIGN: The elegant black color of the wired keyboard complements your tech and decor, adding a stylish and cohesive look to any setup without sacrificing function.
- FULL-SIZED CONVENIENCE: The standard QWERTY layout of this keyboard set offers a familiar typing experience, ideal for both professional tasks and personal use.
Are double-byte characters the same as Unicode?
No. Unicode defines a repertoire of characters and encoding forms; “double-byte character” describes byte length in the context of a particular multibyte character set or code page. Unicode text may be encoded in different ways, and those encodings do not all use two bytes per character.
| Term or encoding | What the byte length means |
|---|---|
| DBCS code page | May use single-byte and two-byte character values; the code page governs their interpretation. |
| UTF-8 | Uses one to four bytes per Unicode character. |
| UTF-16 | Uses two or four bytes per Unicode character. |
The Unicode Consortium’s glossary gives the UTF-8 and UTF-16 byte ranges. In particular, UTF-16 does not mean every character uses exactly two bytes, and a Unicode character is not automatically a double-byte character.
Rank #2
- Reliable Plug and Play: The USB receiver provides a reliable wireless connection up to 33 ft (1), so you can forget about drop-outs and delays and you can take it wherever you use your computer
- Type in Comfort: The design of this keyboard creates a comfortable typing experience thanks to the low-profile, quiet keys and standard layout with full-size F-keys, number pad, and arrow keys
- Durable and Resilient: This full-size wireless keyboard features a spill-resistant design (2), durable keys and sturdy tilt legs with adjustable height
- Long Battery Life: MK270 combo features a 36-month keyboard and 12-month mouse battery life (3), along with on/off switches allowing you to go months without the hassle of changing batteries
- Easy to Use: This wireless keyboard and mouse combo features 8 multimedia hotkeys for instant access to the Internet, email, play/pause, and volume so you can easily check out your favorite sites
Is a fullwidth character two bytes wide?
Not necessarily. “Fullwidth” and “halfwidth” describe display-cell width in East Asian text contexts: a fullwidth glyph typically occupies two cells, while a halfwidth glyph typically occupies one. Display width is separate from encoded storage size. The Unicode Standard discusses these terms and East Asian coding systems in Chapter 18. A glyph’s appearance or number of display cells does not by itself reveal how many bytes encode it.
When should you use the term?
Use “double-byte character” when discussing a DBCS code page or a system that specifically represents a character using a two-byte value. For a file, protocol, or program, identify its declared encoding or code page before interpreting byte sequences. Avoid using the phrase as a synonym for Chinese, Japanese, Korean, or Unicode text: the language alone does not establish the encoding or byte length.
Rank #3
- All-day Comfort: The design of this standard keyboard creates a comfortable typing experience thanks to the deep-profile keys and full-size standard layout with F-keys and number pad
- Easy to Set-up and Use: Set-up couldn't be easier, you simply plug in this corded keyboard via USB on your desktop or laptop and start using right away without any software installation
- Compatibility: This full-size keyboard is compatible with Windows 7, 8, 10 or later, plus it's a reliable and durable partner for your desk at home, or at work
- Spill-proof: This durable keyboard features a spill-resistant design (1), anti-fade keys and sturdy tilt legs with adjustable height, meaning this keyboard is built to last
- Plastic parts in K120 include 51% certified post-consumer recycled plastic*
For new Windows applications, Microsoft recommends Unicode to avoid inconsistencies among code pages and make localization easier. A legacy protocol may still require a particular DBCS code page, in which case that requirement governs the data being exchanged. Microsoft’s code-page guidance covers this recommendation and context.
Quick Recap
Best Value
- All-day Comfort: This USB keyboard creates a comfortable and familiar typing experience thanks to the deep-profile keys and standard full-size layout with all F-keys, number pad and arrow keys
- Built to Last: The spill-proof (2) design and durable print characters keep you on track for years to come despite any on-the-job mishaps; it’s a reliable partner for your desk at home, or at work
- Long-lasting Battery Life: A 24-month battery life (4) means you can go for 2 years without the hassle of changing batteries of your wireless full-size keyboard
- Simply plug the USB receiver into a USB port on your desktop, laptop or netbook computer and start using the keyboard right away without any software installation
- Simply Wireless: Forget about drop-outs and delays thanks to a strong, reliable wireless connection with up to 33 ft range (5); K270 is compatible with Windows 7, 8, 10 or later
Rank #4
- 【Dreamy Rainbow Gaming Keyboard】K521 Gaming Keyboard Adopts a Different LED Backlight Design, Upgraded on the Traditional LED Backlight Effect, Making the Light More Penetrating, Giving You a More Dazzling Visual Effect, Making Your Gaming Process More Enjoyable
- 【One Touch Opens & Visual Feast】The K521 Red Dragon Keyboard has a One-Touch on/off Lighting Button for Added Convenience. It also has a Three-Position Adjustable Breathing Mode and a Four-Position Adjustable Brightness Lighting Mode
- 【Mechanical Feeling & Fast Tapping】The PC Keyboard Keys are Designed for Mechanical Feeling, Giving You a Better Feel During Use and the Ability to Trigger Keys Quickly, Allowing You to Win All Your Games
- 【19 Keys Anti-Ghosting Keyboard】Anti-Ghosting Ensures Every Button Can Be Triggered. This Allows You to Trigger Key Combinations In The Game Accurately, And Each Skill Can Be Accurately Released to Increase Your Winning Rate. Redragon K521 Will Be Your Perfect Partner
- 【12 Multimedia Combination Keys】The K521 Wired Gaming Keyboard is Equipped with 12 Multimedia Keys That Can Greatly Enhance Your Gaming/Office Efficiency and Make It More Convenient to Use
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