Arrow ascii table binary and decimal period


In computing and telecommunicationa control character or non-printing character is a code point a number in a character setthat does not represent a written symbol. They are used as in-band signaling to cause effects other than the addition of a symbol to the text. All other arrow ascii table binary and decimal period are mainly printingprintableor graphic charactersexcept perhaps for the "space" character see ASCII printable characters.

The code DEL is also a control character. Extended ASCII sets defined by ISO added the codes through as control characters, this was primarily done so that if the high bit was stripped it would not change a printing character to a C0 control code, but there have been some assignments here, in particular NEL.

This second set is called the C1 set. These 65 control codes were carried over to Unicode. Unicode added more characters that could be considered controls, but it makes a distinction between these "Formatting characters" such as the Zero-width non-joinerarrow ascii table binary and decimal period the 65 Control characters.

Procedural signs in Morse code are a form of control character. A form of control characters were introduced in the Baudot code: The Murray code added the carriage return CR and line feed LFand other versions of the Baudot code included other control characters. The bell character BELwhich rang a bell to alert operators, was also an early teletype control character.

Even though many control characters are rarely used, the concept of sending device-control information intermixed arrow ascii table binary and decimal period printable characters is so useful that device makers found a way to send hundreds of device instructions. Specifically, they used ASCII code 27 escapefollowed by a series of characters called a "control sequence" or " escape sequence ". Typically, code 27 was sent first in such a sequence to alert the device that the following characters were to be interpreted as a control sequence rather than as plain characters, then one or more characters would follow to specify some detailed action, after which the device would go back to interpreting characters normally.

For example, the sequence of code 27, followed by the printable characters "[2;10H", would cause a DEC VT terminal to move its cursor to the 10th cell of the 2nd line of the screen. But the number of non-standard variations in use is large, especially among printers, where technology has advanced far faster than any standards body can possibly keep up with. Their General Category is "Cc". Formatting codes are distinct, in General Category "Cf". The Cc control characters have no Name in Unicode.

There are a number of techniques to display non-printing characters, which may be illustrated with the bell character in ASCII encoding:. ASCII-based keyboards have a key labelled " Control ", "Ctrl", or rarely "Cntl" which is used much like a shift key, being pressed in combination with another letter or symbol key. In one implementation, the control key generates the code 64 places below the code for the generally uppercase letter it is pressed in combination with i.

For example, pressing "control" and the letter "g" or "G" code in octal or 71 in base 10which is in binaryproduces the code 7 Bell, 7 in base 10, or in binary. For convenience, a lot of terminals accept Ctrl-Space as an alias for Ctrl. This approach is not able to represent the DEL character because of its value codebut Ctrl-?

When the control key is held down, letter keys produce the same control characters regardless of the state of the shift or caps lock keys. In other words, it does not matter whether the key would have produced an upper-case or a lower-case letter. The interpretation of the control key with the space, graphics character, and digit keys ASCII codes 32 to 63 vary between systems. Some will produce the same character code as if the control key were not held down. Other systems translate these keys into control characters when the control key is held down.

Control characters generated using letter keys are thus displayed with the upper-case form of the letter. Keyboards also typically have a few single arrow ascii table binary and decimal period which produce control character codes. For example, the key labelled "Backspace" typically produces code 8, "Tab" code 9, "Enter" or "Return" code 13 though some keyboards might produce code 10 for "Enter". Many keyboards include keys that do not correspond to any ASCII printable or control character, for example cursor control arrows and word processing functions.

The associated keypresses are communicated to computer programs by one of four methods: Keyboards attached to stand-alone personal computers made in the s typically use one or both of the first two methods. Modern computer keyboards generate scancodes that identify the specific physical keys that are pressed; computer software then determines how to handle the keys that are pressed, including any of the four methods described above.

The control characters were designed to fall into a few groups: Printing control characters were arrow ascii table binary and decimal period used to control the physical mechanism of printers, the earliest output device.

An early implementation of this idea was the out-of-band ASA carriage control characters. Later, control characters were integrated into the stream of data to be printed. The carriage return character CRwhen sent to such a device, causes it to arrow ascii table binary and decimal period the character at the edge of the paper at which writing begins it may, or may not, also move the printing position to the next line.

It may or may notdepending on the device and its configuration, also move the printing position to the start of the next line which would be the leftmost position for left-to-right scripts, such as the alphabets used for Western languages, and the rightmost position for right-to-left scripts such as the Hebrew and Arabic alphabets.

The backspace character BS moves the printing position one character space backwards. On printers, this is most often used so the printer can overprint characters to make other, not normally available, characters.

On terminals and other electronic output devices, there are often software or hardware configuration choices which will allow a destruct backspace i. The shift in and shift out characters SO and SI selected alternate character sets, fonts, underlining or other printing modes. Escape sequences were often used to do the same thing. With the advent arrow ascii table binary and decimal period computer terminals that did not physically print on paper and so offered more flexibility regarding screen placement, erasure, and so forth, printing control codes were adapted.

Form feeds, for example, usually cleared the screen, there being no new paper page to move to. More complex escape sequences were developed to take advantage of the flexibility of the new terminals, and indeed of newer printers.

The concept of a control character had always been somewhat limiting, and was extremely so when used with new, much more flexible, hardware. Control sequences sometimes implemented as escape sequences could match the new flexibility and power and became the standard method.

However, there were, and remain, a large variety of standard sequences to choose from. The separators File, Group, Record, and Unit: End of medium EM warns that the tape or other recording medium is ending. The separator control characters are not overloaded; there is no general use of them except to separate data into structured groupings. Their numeric values are contiguous with the space character, which can be considered a member of the group, as a word separator. The transmission control characters were intended to structure a data stream, and to manage re-transmission or graceful failure, as needed, in the face of transmission errors.

The start of heading SOH character was to mark a non-data section of a data stream—the part of a stream containing addresses and other housekeeping data.

The start of text character STX marked the end of the header, and the start of the textual part of a stream. The end of text character ETX marked the end of the data of a message.

The end of transmission block character ETB was used to indicate the end of a block of data, where data was divided into such blocks for transmission purposes.

The escape character ESC was intended to "quote" the next character, if it was another control character it would print it instead of performing the control function. It is almost never used for this purpose today. The substitute character SUB was intended to request a translation of the next character from a arrow ascii table binary and decimal period character to another value, usually by setting bit 5 to zero.

This is handy because some media such as sheets of paper produced by typewriters can transmit only printable characters. However, on MS-DOS systems with files opened in text mode, "end of text" or "end of file" is marked by this Arrow ascii table binary and decimal period character, instead of the Ctrl-C or Ctrl-Dwhich are common on other operating systems. The cancel character CAN signalled that the previous element should be discarded.

The negative acknowledge character NAK is a definite flag for, usually, noting that reception was a problem, and, often, that the current element should be sent again.

The acknowledge character ACK is normally used as a flag to indicate no problem detected with current element.

When a transmission medium is half duplex that is, it can transmit in only one direction at a timethere is usually a master station that can transmit at any time, and one or more slave stations that transmit when they have permission. The enquire character ENQ is generally used by a master station to ask a slave station to send its next message. A slave station indicates that it has completed its transmission by sending the end of transmission character EOT.

The device control codes DC1 to DC4 were originally generic, to be implemented as necessary by each device. However, a universal need in data transmission is to request the sender to stop transmitting when a receiver can't take more data right now. This technique, however implemented, avoids additional wires in the data cable devoted only to transmission arrow ascii table binary and decimal period, which saves money. A sensible protocol for the use of such transmission flow control signals must be used, to avoid potential deadlock conditions, however.

Code 7 BEL is intended to cause an audible signal in arrow ascii table binary and decimal period receiving terminal.

Many of the ASCII control characters were designed for devices of the time that are not often seen today. For example, code 22, "synchronous idle" SYNwas originally sent by synchronous modems which have to send data constantly when there was no actual data to send. Modern systems typically use a start bit to announce the beginning of a transmitted word— this is a feature of asynchronous communication.

Synchronous communication links were more often seen with mainframes, where they were typically run over corporate leased lines to connect a mainframe to another mainframe or perhaps a minicomputer. In paper tape, it is the case when there are no holes. It is convenient to treat this as a fill character with no meaning otherwise. Since the position of a NUL character has no holes punched, it can be replaced with arrow ascii table binary and decimal period other character at a later time, so it was typically used to reserve space, either for correcting errors or for inserting information that would be available at a later time or in another place.

Arrow ascii table binary and decimal period computing it is often used for padding in fixed length records and more arrow ascii table binary and decimal period, to mark the end of a string. Code DELa. Its 7-bit code is all-bits-on in binary, which essentially erased a character cell on a paper tape when overpunched. Paper tape became obsolete in the s, so this clever aspect of ASCII rarely saw any use after that. Some systems such as the original Apples converted it to a backspace.

But because its code is in the range occupied by other printable characters, and because it had no official assigned glyph, many computer equipment vendors used it as an additional printable character often an all-black "box" character useful for erasing text by overprinting with ink. Non-erasable Programmable ROMs are typically implemented as arrays of fusible elements, each representing a bitwhich can only be switched one way, usually from one to zero.

Many file systems do not allow control characters in the filenamesas they may have reserved functions. From Wikipedia, the free encyclopedia. For characters in text applications, see Non-printing character in word processors. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources.

In days of arrow ascii table binary and decimal period, a foundry would pour molten lead into molds to cast type. Today, font foundries pour molten arrow ascii table binary and decimal period into computer outlines to create electronic fonts. Describing fonts as outlines allows one font description to produce fonts for many devices of different resolutions. Of all fonts, the lowliest is the bitmapped screen font.

These can be derived from parent bitmapped fonts. They can also be created in their own right. Electronic font characters, or glyphs, are ordered by assigning each a numeric code.

In Unicode, these numeric assignments are referred to as code points. This is a seven-bit code that fits conveniently into an eight-bit byte, with one bit left over for parity. This parity bit was often used for modem communications over noisy phone lines.

Modern higher-speed modem protocols employ error checking and correction techniques that make use of a parity bit a thing of the past. Thus newer technology allows use of arrow ascii table binary and decimal period eight bits in a byte for encoding character data, even over noisy communications lines.

One eight-bit byte can encode the numbers 0 throughinclusive. ASCII specifies 96 printable characters including Space and Delete plus 32 control characters, for a total of character codes. ISO adopts the entire ASCII character set arrow ascii table binary and decimal period the lower byte values, and uses the eigth bit in a byte to represent additional characters. Many coding schemes have existed arrow ascii table binary and decimal period other scripts.

In general, Unicode adopted these coding schemes where it made sense by fitting them into a portion of the total Unicode encoding space. Unicode specifies its character code points using hexadecimal, an esoteric computer counting scheme traditionally the domain of software and hardware engineers, not graphic artists. Bear with the discussion of bits and bytes and "hex" oh my! You'll also know how to represent a Unicode value in a web page and elsewhere. With apologies to J.

Unicode is revolutionizing the international computing environment. It has broken the one-byte barrier to allow representation of more international and historical scripts than the world has ever seen in earlier computing standards. Its impact is so great that the ISO has ceased all work on their standard series to concentrate efforts on Unicode. Unicode refers to its numeric assignments as code points. A character can be composed from one or more sequential code points.

A code point can be unassigned. A code point also can be assigned to something other than a printing character, such as the special Byte Order Mark BOM described below.

Unicode divides its encoding into planes. Each plane has encodings for two-byte 16 bit values. Each binary bit can represent two values 0 or 1. With 16 bits per Unicode plane, each plane therefore has room to represent up to 65, possible code points. By using twice arrow ascii table binary and decimal period space per code point of older one-byte codes, the very first Unicode plane plane 0 has space for most of the world's modern scripts.

Using twice the storage of older standards is a small price to pay for international language support. Today, most web browsers support Unicode as the default encoding scheme, as does more and more software.

This was enough for most of the world's modern scripts. One notable exception, however, was rare Chinese ideographs. There are well over 65, Chinese ideographs alone. Unicode only uses the first 17 planes. If you're just plain folk, you count in decimal.

There are 10 decimal digits: Computers, on the other hand, count in binary. One binary digit has two possible values hence the name "binary": These two values can be thought of as an electronic switch or memory location being on or off. If we were to take an ordinary decimal number and write it in binary as a string of ones and zeroes, it would take approximately not exactly three times as many digits to write arrow ascii table binary and decimal period a decimal number.

Binary numbers can be written more efficiently by grouping them into clusters of four bits. Hexadecimal from hexa-meaning "six", and decimal, meaning "ten" numbers have 16 values per digit. The letters in hexadecimal notation can be written as upper-case or lower-case letters.

The convention in the Unicode Standard is to write them as upper-case letters. We saw above that Unicode has defined code point assignments for the first 17 planes.

These are planes 0 through 16 decimal. In hexadecimal, the first 17 planes are: A "10" in hexadecimal means one 16 plus zero ones. Incidentally, notice that computers like to begin counting at zero. Four binary bits are represented by exactly one hexadecimal digit. So we can represent a byte value as exactly two hexadecimal digits — everything works out just right.

A four-bit half of a byte is often referred to as a "nybble" or "nibble", which is represented by exactly one hexadecimal digit. This is the range of hexadecimal values of Unicode code points in each Unicode plane.

Hexadecimal numbers are written so that the reader will understand that the values are in hexadecimal, not in some other counting scheme such as decimal. One other common practice there are more, as you'll see later that also appears in the Unicode standard is to write "16" as a subscript after a hexadecimal number, for example F This denotes that the number F is in base Code points in higher planes are written using the plane number in hexadecimal followed by the value within the plane.

Private Use areas can be assigned any desired custom glyphs. The simplest way to represent all possible Unicode code points is with a 32 bit number. Most computers today are based on a 32 bit or 64 bit arrow ascii table binary and decimal period, so this allows computers to manipulate Unicode values as a whole computer "word" of 32 bits on 32 bit architectures, or as a half computer "word" of 32 bits on 64 bit architectures.

Although UTF allows for fast computation on 32 bit and 64 bit computers, it uses four bytes per code point. UTF encodes Unicode code points as one or two 16 bit values. Any code point within the BMP is represented as a single 16 bit value.

Code points above the BMP are broken into an upper half and a lower half, and arrow ascii table binary and decimal period as two 16 bit values. The method or algorithm for this is described below. As we're about to see, this can be manipulated to fit very neatly into UTF encoding, with not a bit to spare. Unicode has 17 planes, which we can write as ranging from 0x00 through 0x The "0x nnnn " notation is a convention from the C computer language, and denotes that the number following the "0x" is hexadecimal.

Chances are you'll run across this form of hexadecimal representation sometime if you're working with Unicode. If we know that the plane of the current code point is beyond the BMP, then the plane number must be in the range 0x01 through 0x If we subtract 1 from the plane number, the resulting adjusted range will be 0x0 through 0xF — this range fits exactly in one hexadecimal digit.

In UTF representation, we take that resulting 20 bit number and divide it into an upper 10 bits and a lower 10 bits. In order to examine bits further, we'll have to cover some binary notation. The table below shows arrow ascii table binary and decimal period four binary digit value of arrow ascii table binary and decimal period hexadecimal digit.

You can use this table to convert hexadecimal digits to and from a binary string of four bits. After splitting the 20 bit Unicode code point into an upper and lower 10 bits, the uppper 10 bits is added to 0xD This resulting value is arrow ascii table binary and decimal period the high surrogate. The lower 10 bits is added to 0xDC This resulting value is called the low surrogate.

The UTF encoded value of a code point beyond plane 0 is then written as two 16 bit values: Some computers store the most significant byte first; some store the most significant byte last. Without getting too side-tracked by a discussion on endian-ness, know that Windows PCs based on Intel processors use the opposite byte ordering of Motorola and PowerPC processors on Macintosh computers.

Therefore this is a very real problem for information exchange that can't be overlooked. If data is exchanged with another computer, some guarantees must exist so that the other computer is either able to determine the byte order or is using the same byte order as the original computer. Inserting a BOM at the beginning of a file allows the receiving computer to determine whether or not it must flip the byte ordering for its own architecture.

If a receiving computer has the opposite byte ordering as the transmitting computer, it will receive this as FFFE 16because the bytes 0xFE and 0xFF will be swapped. The receiver can use this BOM to determine whether or not the bytes in a document must be swapped. If received by a computer with the opposite byte ordering, the receiver will read this as FFFE The receiver can therefore determine that it must flip the byte ordering to read the file. There is another solution to the big endian versus little endian debate and it isn't Gulliver's solution of cracking eggs in the middle.

UTF-8, as its name implies, is based on handling eight bits one byte at a time. Because UTF-8 always handles Unicode values one byte at a time, it is byte order independent.

UTF-8 can therefore be used to exchange data among computers no matter what their native byte ordering is. For this reason, UTF-8 is becoming the de facto standard for encoding web pages.