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Code 128
Code 128 is a high-density linear barcode symbology defined in ISO/IEC 15417:2007. It is used for alphanumeric or numeric-only barcodes. It can encode all 128 characters of ASCII and, by use of an extension symbol (FNC4), the Latin-1 characters defined in ISO/IEC 8859-1. It generally results in more compact barcodes compared to other methods like Code 39, especially when the texts contain mostly digits. Code 128 was developed by the Computer Identics Corporation in 1981. GS1-128 (formerly known as UCC/EAN-128) is a subset of Code 128 and is used extensively worldwide in shipping and packaging industries as a product identification code for the container and pallet levels in the supply chain. Specification A Code 128 barcode has seven sections: # Quiet zone # Start symbol # Encoded data # Check symbol (mandatory) # Stop symbol # Final bar (often considered part of the stop symbol) # Quiet zone The check symbol is calculated from a weighted sum (modular arithmetic, modulo 103) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space (punctuation)
In writing, a space () is a blank area that word divider, separates words, Sentence spacing, sentences, and other written or printed glyphs (characters). Conventions for spacing vary among languages, and in some languages the spacing rules are complex. Inter-word spaces ease the reader's task of identifying words, and avoid outright ambiguities such as "now here" vs. "nowhere". They also provide convenient guides for where a human or program may start new lines. Typesetting can use spaces of varying widths, just as it can use graphic characters of varying widths. Unlike graphic characters, typeset spaces are Typographic alignment, commonly stretched in order to align text. A typewriter, on the other hand, typically has only one width for all characters, including spaces. Following widespread acceptance of the typewriter, some typewriter conventions influenced typography and the design of printed works. Computer representation of text facilitates getting around mechanical and phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carriage Return
A carriage return, sometimes known as a cartridge return and often shortened to CR, or return, is a control character or mechanism used to reset a device's position to the beginning of a line of text. It is closely associated with the line feed and newline concepts, although it can be considered separately in its own right. Typewriters Originally, the term "carriage return" referred to a mechanism or lever on a typewriter. For machines where the type element was fixed and the paper held in a moving ''carriage'', this lever was on the left attached to the moving carriage, and operated after typing a line of text to cause the carriage to return to the far right so the type element would be aligned to the left side of the paper. The lever would also usually ''feed'' the paper to advance to the next line. Many electric typewriters such as IBM Electric or Underwood Electric made carriage return to be another key on the keyboard instead of a lever. The key was usually labeled "car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Form Feed
A page break is a marker in an electronic document that tells the document interpreter the content which follows is part of a new page. A page break causes a form feed to be sent to the printer during spooling of the document to the printer. It is one of the elements that contributes to pagination. Form feed Form feed is a page-breaking ASCII control character. It directs the printer to eject the current page and to continue printing at the top of another. It will often also cause a carriage return. The form feed character code is defined as 12 (0xC in hexadecimal), and may be represented as or . In a related use, can be pressed to clear the screen in Unix shells such as bash, or redraw the screen in TUI programs like vi/emacs. In the C programming language (and other languages derived from C), the form feed character is represented as '\f'. Unicode also provides the character as a printable symbol for a form feed (not as the form feed itself). The form feed character is con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertical Tab
The tab key (abbreviation of tabulator key or tabular key) on a keyboard is used to advance the cursor to the next tab stop. History The word ''tab'' derives from the word ''tabulate'', which means "to arrange data in a tabular, or table, form". When a person wanted to type a table (of numbers or text) on a typewriter, there was a lot of time-consuming and repetitive use of the space bar and backspace key. To simplify this, a horizontal bar was placed in the mechanism called the tabulator rack. Pressing the tab key would advance the carriage to the next tabulator stop. The original tabulator stops were adjustable clips that could be arranged by the user on the tabulator rack. Fredric Hillard filed a patent application for such a mechanism in 1900. The tab mechanism came into its own as a rapid and consistent way of uniformly indenting the first line of each paragraph. Often a first tab stop at 5 or 6 characters was used for this, far larger than the indentation used whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line Feed
A newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a sequence of characters, is used to signify the end of a line (text file), line of text and the start of a new one. History In the mid-1800s, long before the advent of teleprinters and teletype machines, Morse code operators or telegraphists invented and used Prosigns for Morse code, Morse code prosigns to encode white space text formatting in formal written text messages. In particular, the International Morse code, Morse prosign (mnemonic break text), represented by the concatenation of literal textual Morse codes "B" and "T" characters, sent without the normal inter-character spacing, is used in Morse code to encode and indicate a ''new line'' or ''new section'' in a formal text message. Later, in the age of modern teleprinters, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tab Key
The tab key (abbreviation of tabulator key or tabular key) on a keyboard is used to advance the cursor to the next tab stop. History The word ''tab'' derives from the word ''tabulate'', which means "to arrange data in a tabular, or table, form". When a person wanted to type a table (of numbers or text) on a typewriter, there was a lot of time-consuming and repetitive use of the space bar and backspace key. To simplify this, a horizontal bar was placed in the mechanism called the tabulator rack. Pressing the tab key would advance the carriage to the next tabulator stop. The original tabulator stops were adjustable clips that could be arranged by the user on the tabulator rack. Fredric Hillard filed a patent application for such a mechanism in 1900. The tab mechanism came into its own as a rapid and consistent way of uniformly indenting the first line of each paragraph. Often a first tab stop at 5 or 6 characters was used for this, far larger than the indentation used whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backspace
Backspace (, ⌫) is the keyboard key that in typewriters originally pushed the carriage one position backwards, and in modern computer systems typically moves the display cursor one position backwards,The meaning of "backwards" depends on the direction of the text, and could get complicated in text involving several Bidirectional text, bidirectional categories. deletes the character at that position, and shifts back any text after"after" here implies on the same logical line of text that position by one character. Nomenclature Although the term "backspace" is the traditional name of the key which steps the carriage back and/orin some correcting typewriters it did both deletes the previous character, typically to the left of the cursor, the actual key may be labeled in a variety of ways, for example ''delete'', ''erase'', or with a left pointing arrow. A dedicated symbol for "backspace" exists as Miscellaneous Technical#Block, U+232B ⌫ but its use as a keyboard label is not univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Character
A bell character (sometimes bell code) is a device control code originally sent to ring a small electromechanical bell on tickers and other teleprinters and teletypewriters to alert operators at the other end of the line, often of an incoming message. Though tickers punched the bell codes into their tapes, printers generally do not print a character when the bell code is received. Bell codes are usually represented by the label "BEL". They have been used since 1870 (initially in the Baudot code). To maintain backward compatibility, video display terminals (VDTs) that replaced teletypewriters included speakers or buzzers to perform the same function, as did the personal computers that followed. Modern terminal emulators often integrate the warnings to the desktop environment (e.g., the macOS Terminal will play the system warning sound) and also often offer a silent ''visual bell'' feature that flashes the terminal window briefly. Representations In ASCII the bell characte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acknowledge Character
In data networking, telecommunications, and computer buses, an acknowledgement (ACK) is a signal that is passed between communicating processes, computers, or devices to signify acknowledgment, or receipt of message, as part of a communications protocol. Correspondingly a negative-acknowledgement (NAK or NACK) is a signal that is sent to reject a previously received message or to indicate some kind of error. Acknowledgments and negative acknowledgments inform a sender of the receiver's state so that it can adjust its own state accordingly. Acknowledgment signal types The ASCII code point for ACK is 0x06 (binary 0000 0110). By convention a receiving device sends an ACK to indicate it successfully received a message. ASCII also provides a NAK code point (0x15, binary 0001 0101) which can be used to indicate the receiving device cannot, or will not, comply with the message. Unicode provides visible symbols for these ASCII characters, U+2406 (␆) and U+2415 (␕). ACK and NAK ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enquiry (computer Communications)
In computer communications, enquiry is a transmission-control character that requests a response from the receiving station with which a connection has been set up. It represents a signal intended to trigger a response at the receiving end, to see whether it is still present. The response, an answer-back code to the terminal that transmitted the WRU (who are you) signal, may include station identification, the type of equipment in service, and the status of the remote station. Some teleprinters had a "programmable" drum, which could hold a 20- or 22-character message. The message was encoded on the drum by breaking tabs off the drum. This sequence could be transmitted upon receipt of an enquiry signal, if enabled, or by pressing the "Here is" key on the keyboard. The 5-bit ITA2 has an enquiry character, as do the later ASCII and EBCDIC. In the 1960s, DEC routinely disabled the answerback feature on Teletype Model 33 terminals because it interfered with the use of the pape ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
End-of-transmission Character
In telecommunications, an End-of-Transmission character (EOT) is a transmission (telecommunications), transmission control character. Its intended use is to indicate the conclusion of a transmission that may have included one or more texts and any associated message headings. An EOT is often used to initiate other functions, such as releasing circuits, disconnecting terminals, or placing receive terminals in a standby (electricity), standby condition. Its most common use today is to cause a Unix computer terminal, terminal driver to signal end of file and thus exit programs that are awaiting input. In ASCII and Unicode, the character is encoded at . It can be referred to as , in caret notation. Unicode provides the character for when EOT needs to be displayed graphically. In addition, can also be used as a graphic representation of EOT; it is defined in Unicode as "symbol for End of Transmission". Meaning in Unix The EOT character in Unix is different from the Control-Z in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
