# Digital Electronics/Printable version

The current, editable version of this book is available in Wikibooks, the open-content textbooks collection, at
https://en.wikibooks.org/wiki/Digital_Electronics

# Number Base System

In digital electronics how information is represented is key and there are different radices, i.e. number bases, that a numbering system can use, with the most common ones being: binary (base-2), octal (base-8), decimal (base 10) and hexadecimal (base 16). When a reference is made to a numbering system's base, i.e. its' radix, the base number represents the number of digits used in that numbering system. As an example, we are all familiar with the decimal numbering system and the digits used it are: 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9. The numbering systems that have a base/radix less than 10 recycle the "digits" used to be common with the decimal numbering system. Therefore, the digits for binary are: 0 and 1, the digits for octal are: 0, 1, 2, 3, 4, 5, 6 and 7. For the hexadecimal numbering system, base 16, the digits are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F.
The decimal numbering is obviously linked to the fact that us humans have 10 fingers...10 digits. However, the other "common" numbering systems in digital electronics are linked to logic, in particularly boolean logic and boolean algebra as developed by George Boole. In logic, including the philosophical kind, there can only be two answers: TRUE or FALSE. In digital electronics, we can represent TRUE as a high voltage (historically 5 Volts, but it has changed to save power) which we denote as a 1 and we represent FALSE as low voltage (0 Volts, but lower voltages can also be used too) which we denote as a 0. Therefore, with two values to work with we then have the binary numbering system. The octal numbering is simply a more compact group of three binary digits. So instead of having to type "101" we can just type "5"; assuming that the numbering system is known to be octal based. In a similar manner, hexadecimal based numbering system is based on a grouping of four binary digits, so "D" is easier to type instead of "1101"

## Beyond Digits, Representing Numbers

Now that we understand a numbering system's radix, the next step is to use these digits to present numbers, ideally large numbers. Independent of the numbering system's radix, the order of digits as they are listed in the representation of a number is of GREAT "significance", pardon the pun, and needs to be fully understood to be able to use any numbering system properly; even the decimal numbering system. The digit furthest to the right has a numerical weight of $(radix)^{0}$, which is always 1 given that any number raised to the zero power is one. The next digit moving to the left has a numerical weight of $(radix)^{1}$, which is the first digit where the radix value begins to being a factor. The weighting for each subsequent digit continues to increase by one with respect to the "power" that the radix is raised. And like in our more traditional decimal numbering systems there are ALWAYS zero digits in front of the highest weighted digit, but we simply do not bother writing all those zeros as such zeroes are not significant. The same is true with other radices, hence the order of the digits is representing a number in any radix is significant.
The next sections provide illustrations on how numbers are represented in the differing radices.

## Number of Base Two

Base two numbers only use the two digits 0 and 1 . Any number greater than 1 is represented by a series of 0 and 1 digits
    $1110=1*2^{3}+1*2^{2}+1*2^{1}+0*2^{0}$ = 14
Numbers that contain only two digit 0 and 1 are called Binary Numbers. Each 0 or 1 is called a Bit, from binary digit. A binary number of 4 bits is called a Nibble. A binary number of 8 bits is called a Byte. A binary number of 16 bits is called a Word on some systems, on others a 32-bit number is called a Word while a 16-bit number is called a Halfword.
Using 2 bit 0 and 1 to form
    a binary number of 1 bit, there are 2 such numbers 0 and 1
    a binary number of 2 bit, there are 4 such numbers 00, 01, 10, 11
    a binary number of 3 bit, there are 8 such numbers 000, 001, 010, 011, 100, 101, 110, 111
    a binary number of 4 bit, there are 16 such numbers 0000, 0010, 0100, 0110, 1000, 1010, 1100, ..., 1111
Therefore , using n bits there are 2$^n$ binary numbers of n bits

## Numbers of Base Ten

Base ten numbers use ten digits, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. Any number greater than 9 is represented by a series of digits in the 0 through 9 range.
    $14=1*10^{1}+4*10^{0}$

## Numbers of Base sixteen(hexa decimal)

Base sixteen numbers use sixteen digits 0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f. any number greater than 15 is represented by digits in the 0 through f range.

## Communication (Conversion) between numbers of Different base

The same number 14 expressed
    in base ten is 14
    in base two is 1110 .
Hence, any number in our base ten system can be represented by a binary number of certain bit

# Logic Operations
## Logic Operation

    Logic BUFFER perform a logic operation on a input . Output is the same as Input
    Logic NOT perform a logic operation on a input . Output is the invert of Input
    Logic AND perform a logic operation on two input to yield a result at the output. Output is High only when both Inputs are High
    Logic OR perform a logic operation on two input to yield a result at the output. Output is Low only when both Inputs are Low
    Logic XOR perform a logic operation on two input to yield a result at the output. Output is Low only when both Inputs are the same and Output is High only when both Inputs are different

## Digital Logic Equation

If A and B is Input and Y as Output then
    Logic BUFFER → Y = A
    Logic NOT → Y = NOT A
    Logic AND → Y = A AND B
    Logic OR → Y = A OR B
    Logic XOR → Y = A XOR B

## Digital Truth Table

The logic operation of any logic above can be summarized in a table called a truth table.
If High is 1 and Low is 0 then

## Digital Gates Construction

Each Logic can be constructed from electronic components to form a circuit of a device called Digital Gates to perform the logic operation

# Mathematical Operations
## Basic Mathematics
### Addition

    0 + 0 = 0
    0 + 1 = 1
    1 + 0 = 1
    1 + 1 = 1 0

### Subtraction

    0 - 0 = 0
    0 - 1 = 0 1
    1 - 0 = 1
    1 - 1 = 0

### Multiplication

    0 x 0 = 0
    0 x 1 = 0
    1 x 0 = 0
    1 x 1 = 1

### Division

    0 / 0 = x
    0 / 1 = 0
    1 / 0 = x
    1 / 1 = 1

## Logic Mathematics

NOT AND OR XOR NAND

# Building Circuits with Breadboards

One of the best ways to learn how digital circuits work is to build them with an inexpensive solderless breadboard.
They typically come in three sizes
* mini
* half (around 400 connection points)
* full

# Logic Gates
## Family Logic Gates

* Fundamental Digital Gates
* Combinational Gates
* Basic Logic Gates Summary
* Logic NAND

## Reference

* Logic Gate

# Logic Gates/Fundamental Digital Gates
## Digital Gates

Digital gate is a Digital Device used to perform the logic operation on the input(s) to produce an equivalent logic in the output. The output produced from the inputs are listed in a table called a Truth table. The relation between output and inputs can also be represented by a mathematic equation .
There are 5 basic digital gates used to perform Logic Operation namely Buffer, NOT, AND, OR, XOR

## Basic Digital Gates

    Basic Logic GatesSymbolMathmatical FormulaTruth Table BufferQ = A AQ 00 11 NOTQ = NOT A AQ 01 10 ANDQ = A . B ABQ 000 010 100 111 ORQ = A + B ABQ 000 011 101 111 XORQ = A (+) B ABQ 000 011 101 110

# Logic Gates/Combinational Gates
## Combination gates

More than one logic gates can be connected to produce new logic gates

### Buffer

    Basic Logic GatesCombinational GatesSymbolMathmatical FormulaTruth Table Buffer Y = is NOT NOT A Y = AA Q 0 0 1 1

### NOT Gate

    Digital GateCombinational GatesSymbolMathematical ExpressionTruth Table NOT Gate Y = is NOT AA Y 0 1 1 0

### NAND Gate

    Digital GateCombinational GateSymbolMathematical ExpressionTruth Table Buffer Y = is NOT A.BA B Y 0 0 1 0 1 1 1 0 1 1 1 0

### NOR Gate

    Digital GateCombinational GateSymbolMathematical ExpressionTruth Table NOT Y = is NOT A+BA B Y 0 0 1 0 1 0 1 0 0 1 1 0

### XNOR Gate

    Basic GatesCombinational GateSymbolMathematical FormulaTruth Table NOT Gate Y = is NOT AxorBA B Q 0 0 1 0 1 0 1 0 0 1 1 1

# Logic Gates/Basic Logic Gates Summary
## Logic Gates Summary

The table below summarize all the Basic Digital Gates and their characteristics
    Basic Logic GatesSymbolMathmatical FormulaTruth Table BufferQ = AA Q 0 0 1 1 NOTQ = NOT AA Q 0 1 1 0 ANDQ = A . BA B Q 0 0 0 0 1 0 1 0 0 1 1 1 NANDQ = NOT (A . B)A B Q 0 0 1 0 1 1 1 0 1 1 1 0 ORQ = A + BA B Q 0 0 0 0 1 1 1 0 1 1 1 1 NORQ = NOT (A + B)A B Q 0 0 1 0 1 0 1 0 0 1 1 0 XORQ = (A + B) . NOT (A . B)A B Q 0 0 0 0 1 1 1 0 1 1 1 0 XNORQ = NOT ( (A + B) . NOT (A . B) )A B Q 0 0 1 0 1 0 1 0 0 1 1 1

# Logic Gates Summary

The table below summarize all the Basic Digital Gates and their characteristics
    Basic Logic GatesSymbolMathmatical FormulaTruth TableConstructions BufferQ = AA Q 0 0 1 1 NOTQ = NOT AA Q 0 1 1 0 ANDQ = A . BA B Q 0 0 0 0 1 0 1 0 0 1 1 1 NANDQ =NOT (A . B)A B Q 0 0 1 0 1 1 1 0 1 1 1 0 ORQ = A + BA B Q 0 0 0 0 1 1 1 0 1 1 1 1 NORQ = NOT (A + B)A B Q 0 0 1 0 1 0 1 0 0 1 1 0 XORQ = A + BA B Q 0 0 0 0 1 1 1 0 1 1 1 0 XNORQ = A + BA B Q 0 0 0 0 1 1 1 0 1 1 1 1

# Mathematic and Logic Operations

* Digital Adder
* Digital Subtractor
* Digital Decoder
* Digital Encoder

# Synchronous Device
## Synchronous Device

* Flip Flop
* Register
* Counter

# Asychronous Device
## Asychronous Device

* Digital Multiplexer
* Digital DeMultiplexing

# Digital Data
## Digital Data

Digital Data is a Binary Numbers of two bits 0 and 1 . A 0 & 1 could be
* 0v & 5v
* Switch Opened & Switch Closed
* High & Low

## Data Communication
### Parallel In Parallel Out

Input Data is entered in Parallel and get out in Parallel
Data In --> Data Out
    0 --> 0
    1 --> 1
    0 --> 0
    1 --> 1

### Parallel In Series Out

Input Data is entered in Parallel and get out in Series
Data In
    0
    1
    0
    1
Data Out
    0101

# Data Encoder
## Digital Encoder Introduction

Digital Encoder is a Digital Device that uses binary number of n bit to represent a number of base ten . Binary number of n bit is called Binary Coded Decimal (BCD), a coding scheme used in digital to encode informations
If there are two control lines A and B , we can have 4 4-bit-binary-numbers a$_3$a$_2$a$_1$a$_0$ which can be used to represent a number of base ten from 0 to 3
    ABa$_3$a$_2$a$_1$a$_0$Decimal Number 0000000 0100011 1000102 1100113

## Digital Encoder Types
### BCD - Binary Coded Decimal

In order to encode decimal number from 0 - 9 using Binary Coded Decimal Scheme , 10 4-bit-Binary-numbers are used
    ABa$_3$a$_2$a$_1$a$_0$Decimal Number 0000000 0100011 1000102 1100113 1101004 1101015 1101106 1101117 1110008 1110019

### ASCII Code

ASCII stands for American Standard Communication Information Interchange is the first standard introduced in North America for Information exchange . ASCII uses 7 bits Binary numbers to represent information in human language
* Number from 0 to 9
* Capital A to Z
* Common a to z
Code 0x20 (hexadecimal), the space character, denotes the space between words, as produced by the space-bar of a keyboard. The space character is considered an invisible graphic rather than a control character. Codes 0x21 to 0x7E, known as the printable characters, represent letters, digits, punctuation marks, and a few miscellaneous symbols.
    BinaryOctDecHexGlyph 010 00000403220space 010 00010413321! 010 00100423422" 010 00110433523# 010 01000443624$ 010 01010453725% 010 01100463826& 010 01110473927' 010 10000504028( 010 10010514129) 010 1010052422A* 010 1011053432B+ 010 1100054442C, 010 1101055452D- 010 1110056462E. 010 1111057472F/ 011 000006048300 011 000106149311 011 001006250322 011 001106351333 011 010006452344 011 010106553355 011 011006654366 011 011106755377 011 100007056388 011 100107157399 011 1010072583A: 011 1011073593B; 011 1100074603C< 011 1101075613D= 011 1110076623E> 011 1111077633F?
| Binary | Oct | Dec | Hex | Glyph |
| 100 0000 | 100 | 64 | 40 | @ |
| 100 0001 | 101 | 65 | 41 | A |
| 100 0010 | 102 | 66 | 42 | B |
| 100 0011 | 103 | 67 | 43 | C |
| 100 0100 | 104 | 68 | 44 | D |
| 100 0101 | 105 | 69 | 45 | E |
| 100 0110 | 106 | 70 | 46 | F |
| 100 0111 | 107 | 71 | 47 | G |
| 100 1000 | 110 | 72 | 48 | H |
| 100 1001 | 111 | 73 | 49 | I |
| 100 1010 | 112 | 74 | 4A | J |
| 100 1011 | 113 | 75 | 4B | K |
| 100 1100 | 114 | 76 | 4C | L |
| 100 1101 | 115 | 77 | 4D | M |
| 100 1110 | 116 | 78 | 4E | N |
| 100 1111 | 117 | 79 | 4F | O |
| 101 0000 | 120 | 80 | 50 | P |
| 101 0001 | 121 | 81 | 51 | Q |
| 101 0010 | 122 | 82 | 52 | R |
| 101 0011 | 123 | 83 | 53 | S |
| 101 0100 | 124 | 84 | 54 | T |
| 101 0101 | 125 | 85 | 55 | U |
| 101 0110 | 126 | 86 | 56 | V |
| 101 0111 | 127 | 87 | 57 | W |
| 101 1000 | 130 | 88 | 58 | X |
| 101 1001 | 131 | 89 | 59 | Y |
| 101 1010 | 132 | 90 | 5A | Z |
| 101 1011 | 133 | 91 | 5B | [ |
| 101 1100 | 134 | 92 | 5C | \ |
| 101 1101 | 135 | 93 | 5D | ] |
| 101 1110 | 136 | 94 | 5E | ^ |
| 101 1111 | 137 | 95 | 5F | _ |
| Binary | Oct | Dec | Hex | Glyph |
| 110 0000 | 140 | 96 | 60 | ` |
| 110 0001 | 141 | 97 | 61 | a |
| 110 0010 | 142 | 98 | 62 | b |
| 110 0011 | 143 | 99 | 63 | c |
| 110 0100 | 144 | 100 | 64 | d |
| 110 0101 | 145 | 101 | 65 | e |
| 110 0110 | 146 | 102 | 66 | f |
| 110 0111 | 147 | 103 | 67 | g |
| 110 1000 | 150 | 104 | 68 | h |
| 110 1001 | 151 | 105 | 69 | i |
| 110 1010 | 152 | 106 | 6A | j |
| 110 1011 | 153 | 107 | 6B | k |
| 110 1100 | 154 | 108 | 6C | l |
| 110 1101 | 155 | 109 | 6D | m |
| 110 1110 | 156 | 110 | 6E | n |
| 110 1111 | 157 | 111 | 6F | o |
| 111 0000 | 160 | 112 | 70 | p |
| 111 0001 | 161 | 113 | 71 | q |
| 111 0010 | 162 | 114 | 72 | r |
| 111 0011 | 163 | 115 | 73 | s |
| 111 0100 | 164 | 116 | 74 | t |
| 111 0101 | 165 | 117 | 75 | u |
| 111 0110 | 166 | 118 | 76 | v |
| 111 0111 | 167 | 119 | 77 | w |
| 111 1000 | 170 | 120 | 78 | x |
| 111 1001 | 171 | 121 | 79 | y |
| 111 1010 | 172 | 122 | 7A | z |
| 111 1011 | 173 | 123 | 7B | { |
| 111 1100 | 174 | 124 | 7C | | |
| 111 1101 | 175 | 125 | 7D | } |
| 111 1110 | 176 | 126 | 7E | ~ |

## Reference
# Data Selector
## Data Selector

Data Selector take one data input and a number of selection inputs, and they have several outputs. They forward the data input to one of the outputs depending on the values of the selection inputs.
Demultiplexers are sometimes convenient for designing general purpose logic, because if the demultiplexer's input is always true, the demultiplexer acts as a decoder. This means that any function of the selection bits can be constructed by logically OR-ing the correct set of outputs.

# ISO
## ISO Standard

Template:Infobox Organization The International Organization for Standardization (Organisation internationale de normalisation), widely known as ISO (Template:Pron-en), is an international-standard-setting body composed of representatives from various national standards organizations. Founded on 23 February 1947, the organization promulgates worldwide proprietary industrial and commercial standards. It has its headquarters in Geneva, Switzerland. While ISO defines itself as a non-governmental organization, its ability to set standards that often become law, either through treaties or national standards, makes it more powerful than most non-governmental organizations. In practice, ISO acts as a consortium with strong links to governments.

## Name and abbreviation

The organization's logos in its two official languages, English and French, include the word ISO (Template:Pron-en), and it is usually referred to by this short-form name. ISO is not an acronym or initialism for the organization's full name in either official language. Rather, the organization adopted ISO based on the Greek word isos (ἴσος), meaning equal. Recognizing that the organization’s initials would be different in different languages, the organization's founders chose ISO as the universal short form of its name. This, in itself, reflects the aim of the organization: to equalize and standardize across cultures.

## International Standards and other publications

    See also: List of ISO standards
ISO's main products are the International Standards. ISO also publishes Technical Reports, Technical Specifications, Publicly Available Specifications, Technical Corrigenda, and Guides.
International Standards are identified in the format ISO[/IEC][/ASTM] [IS] nnnnn[:yyyy] Title, where nnnnn is the number of the standard, yyyy is the year published, and Title describes the subject. IEC for International Electrotechnical Commission is included if the standard results from the work of ISO/IEC JTC1 (the ISO/IEC Joint Technical Committee). ASTM (American Society for Testing and Materials)is used for standards developed in cooperation with ASTM International. The date and IS are not used for an incomplete or unpublished standard, and may under some circumstances be left off the title of a published work.
Technical Reports are issued when "a technical committee or subcommittee has collected data of a different kind from that which is normally published as an International Standard". such as references and explanations. The naming conventions for these are the same as for standards, except TR prepended instead of IS in the report's name. Examples:
* ISO/IEC TR 17799:2000 Code of Practice for Information Security Management
* ISO/TR 19033:2000 Technical product documentation — Metadata for construction documentation
Technical Specifications can be produced when "the subject in question is still under development or where for any other reason there is the future but not immediate possibility of an agreement to publish an International Standard". Publicly Available Specifications may be "an intermediate specification, published prior to the development of a full International Standard, or, in IEC may be a 'dual logo' publication published in collaboration with an external organization". Both are named by convention similar to Technical Reports, for example:
* ISO/TS 16952-1:2006 Technical product documentation — Reference designation system — Part 1: General application rules
* ISO/PAS 11154:2006 Road vehicles — Roof load carriers
ISO sometimes issues a Technical Corrigendum. These are amendments to existing standards because of minor technical flaws, usability improvements, or to extend applicability in a limited way. Generally, these are issued with the expectation that the affected standard will be updated or withdrawn at its next scheduled review.
ISO Guides are meta-standards covering "matters related to international standardization". They are named in the format "ISO[/IEC] Guide N:yyyy: Title", for example:
* ISO/IEC Guide 2:2004 Standardization and related activities — General vocabulary
* ISO/IEC Guide 65:1996 General requirements for bodies operating product certification

## Standardization process

A standard published by ISO/IEC is the last stage of a long process that commonly starts with the proposal of new work within a committee. Here are some abbreviations used for marking a standard with its status:
* PWI - Preliminary Work Item
* NP or NWIP - New Proposal / New Work Item Proposal (e.g. ISO/IEC NP 23007)
* AWI - Approved new Work Item (e.g. ISO/IEC AWI 15444-14)
* WD - Working Draft (e.g. ISO/IEC WD 27032)
* CD - Committee Draft (e.g. ISO/IEC CD 23000-5)
* FCD - Final Committee Draft (e.g. ISO/IEC FCD 23000-12)
* DIS - Draft International Standard (e.g. ISO/IEC DIS 14297)
* FDIS - Final Draft International Standard (e.g. ISO/IEC FDIS 27003)
* PRF - Proof of a new International Standard (e.g. ISO/IEC PRF 18018)
* IS - International Standard (e.g. ISO/IEC 13818-1:2007)
Abbreviations used for amendments:
* NP Amd - New Proposal Amendment (e.g. ISO/IEC 15444-2:2004/NP Amd 3)
* AWI Amd - Approved new Work Item Amendment (e.g. ISO/IEC 14492:2001/AWI Amd 4)
* WD Amd - Working Draft Amendment (e.g. ISO 11092:1993/WD Amd 1)
* CD Amd / PDAmd - Committee Draft Amendment / Proposed Draft Amendment (e.g. ISO/IEC 13818-1:2007/CD Amd 6)
* FPDAmd / DAM (DAmd) - Final Proposed Draft Amendment / Draft Amendment (e.g. ISO/IEC 14496-14:2003/FPDAmd 1)
* FDAM (FDAmd) - Final Draft Amendment (e.g. ISO/IEC 13818-1:2007/FDAmd 4)
* PRF Amd - (e.g. ISO 12639:2004/PRF Amd 1)
* Amd - Amendment (e.g. ISO/IEC 13818-1:2007/Amd 1:2007)
Other abbreviations:
* TR - Technical Report (e.g. ISO/IEC TR 19791:2006)
* DTR - Draft Technical Report (e.g. ISO/IEC DTR 19791)
* TS - Technical Specification (e.g. ISO/TS 16949:2009)
* DTS - Draft Technical Specification (e.g. ISO/DTS 11602-1)
* TTA - Technology Trends Assessment (e.g. ISO/TTA 1:1994)
* IWA - International Workshop Agreement (e.g. IWA 1:2005)
* Cor - Technical Corrigendum (e.g. ISO/IEC 13818-1:2007/Cor 1:2008)
International Standards are developed by ISO technical committees (TC) and subcommittees (SC) by a process with six steps:
* Stage 1: Proposal stage
* Stage 2: Preparatory stage
* Stage 3: Committee stage
* Stage 4: Enquiry stage
* Stage 5: Approval stage
* Stage 6: Publication stage
The TC/SC may set up working groups (WG) of experts for the preparation of a Working Drafts. Subcommittees may have several working groups, which can have several Sub Groups (SG).
Stages in the development process of an ISO standard :
| Stage code | Stage | Associated document name | Abbreviations | Description |
| 00 | Preliminary stage | Preliminary work item | PWI | |
| 10 | Proposal stage | New work item proposal | NP or NWIP, NP Amd/TR/TS/IWA | |
| 20 | Preparatory stage | Working draft(s) | AWI, AWI Amd/TR/TS, WD, WD Amd/TR/TS | |
| 30 | Committee stage | Committee draft(s) | CD, CD Amd/Cor/TR/TS, PDAmd (PDAM), PDTR, PDTS | |
| 40 | Enquiry stage | Enquiry draft | DIS, FCD, FPDAmd, DAmd (DAM), FPDISP, DTR, DTS | (CDV in IEC) |
| 50 | Approval stage | final draft International Standard | FDIS, FDAmd (FDAM), PRF, PRF Amd/TTA/TR/TS/Suppl, FDTR | |
| 60 | Publication stage | International Standard | ISO TR, TS, IWA, Amd, Cor | |
| 90 | Review stage | | ISO TR, TS, IWA, Amd, Cor | |
| 95 | Withdrawal stage | | | |
It is possible to omit certain stages, if there is a document with a certain degree of maturity at the start of a standardization project - for example a standard developed by another organization. ISO/IEC Directives allow also the so-called "Fast-track procedure". In this procedure a document is submitted directly for approval as a draft International Standard (DIS) to the ISO member bodies or as a final draft International Standard (FDIS) if the document was developed by an international standardizing body recognized by the ISO Council.
The first step - a proposal of work (New Proposal) is approved at the relevant subcommittee or technical committee (e.g. SC29 and JTC1 respectively in the case of Moving Picture Experts Group - ISO/IEC JTC1/SC29/WG11). A working group (WG) of experts is set up by the TC/SC for the preparation of a Working Draft. When the scope of a new work is sufficiently clarified, some of the working groups (e.g. MPEG) usually make open request for proposals - known as "Call for proposals". The first document that is produced for example for audio and video coding standards is called a Verification Model (VM) (previously also called a Simulation and Test Model). When a sufficient confidence in the stability of the standard under development is reached, a Working Draft (WD) is produced. This is in the form of a standard but is kept internal to working group for revision. When a Working Draft is sufficiently solid and the working group is satisfied that it has developed the best technical solution to the problem being addressed, it becomes Committee Draft (CD). If it is required, it is then sent to the P-members of the TC/SC (National Bodies) for ballot. The CD becomes Final Committee Draft (FCD) if the number of positive votes is above the quorum. Successive committee drafts may be considered until consensus is reached on the technical content. When it is reached, the text is finalized for submission as a draft International Standard (DIS). The text is then submitted to National Bodies for voting and comment within a period of five months. It is approved for submission as a final draft International Standard (FDIS) if a two-thirds majority of the P-members of the TC/SC are in favour and not more than one-quarter of the total number of votes cast are negative. ISO will then hold a ballot with National Bodies where no technical changes are allowed (yes/no ballot), within a period of two months. It is approved as an International Standard (IS) if a two-thirds majority of the P-members of the TC/SC is in favour and not more than one-quarter of the total number of votes cast are negative. After approval, only minor editorial changes are introduced into the final text. The final text is sent to the ISO Central Secretariat which publishes it as the International Standard.

## ISO document copyright

ISO documents are copyrighted and ISO charges for copies of most. ISO does not, however, charge for most draft copies of documents in electronic format. Although useful, care must be taken using these drafts as there is the possibility of substantial change before it becomes finalized as a standard. Some standards by ISO and its official U.S. representative (and the International Electrotechnical Commission's via the U.S. National Committee) are made freely available.

## Members

ISO has 158 national members, out of the 195 total countries in the world.
ISO has three membership categories:
* Member bodies are national bodies that are considered to be the most representative standards body in each country. These are the only members of ISO that have voting rights.
* Correspondent members are countries that do not have their own standards organization. These members are informed about ISO's work, but do not participate in standards promulgation.
* Subscriber members are countries with small economies. They pay reduced membership fees, but can follow the development of standards.
Participating members are called "P" members as opposed to observing members which are called "O" members.

## Products named after ISO

The fact that many of the ISO-created standards are ubiquitous has led, on occasion, to common use of "ISO" to describe the actual product that conforms to a standard. Some examples of this are:
* CD images end in the file extension "ISO" to signify that they are using the ISO 9660 standard filesystem as opposed to another file system - hence CD images are commonly referred to as "ISOs". Virtually all computers with CD-ROM drives can read CDs that use this standard. Some DVD-ROMs also use ISO 9660 filesystems.
* Photographic film's sensitivity to light, its "film speed," is described by ISO 5800:1987. Hence, the film's speed is often referred to as its "ISO number."

## ISO/IEC Joint Technical Committee 1

To deal with the consequences of substantial overlap in areas of standardization and work related to information technology, ISO and IEC formed a Joint Technical Committee known as the ISO/IEC JTC1. It was the first such joint committee. The second joint committee was created in 2009 - Joint Project Committee - Energy efficiency and renewable energy sources - Common terminology (ISO/IEC/JTC 2).

## IWA document

Like ISO/TS, International Workshop Agreement (IWA) is another armoury of ISO for providing rapid response to requirements for standardization in areas where the technical structures and expertise are not currently in place. The utility harmonizes technical urgency industrial wide.

## Criticism

With the exception of a small number of isolated standards, ISO standards are normally not available free of charge, but for a purchase fee, which has been seen by some as too expensive for small Open source projects.
The ISO/IEC JTC1 fast-track procedures ("Fast-track" as used by OOXML and "PAS" as used by OpenDocument) have garnered criticism in relation to the standardization of Office Open XML (ISO/IEC 29500). Martin Bryan, outgoing Convenor of ISO/IEC JTC1/SC34 WG1, is quoted as saying:
   I would recommend my successor that it is perhaps time to pass WG1’s outstanding standards over to OASIS, where they can get approval in less than a year and then do a PAS submission to ISO, which will get a lot more attention and be approved much faster than standards currently can be within WG1.
   The disparity of rules for PAS, Fast-Track and ISO committee generated standards is fast making ISO a laughing stock in IT circles. The days of open standards development are fast disappearing. Instead we are getting 'standardization by corporation'.
Computer security entrepreneur and Ubuntu investor, Mark Shuttleworth, commented on the Standardization of Office Open XML process by saying
   I think it de-values the confidence people have in the standards setting process,
and Shuttleworth alleged that ISO did not carry out its responsibility. He also noted that Microsoft had intensely lobbied many countries that traditionally had not participated in ISO and stacked technical committees with Microsoft employees, solution providers and resellers sympathetic to Office Open XML.
   When you have a process built on trust and when that trust is abused, ISO should halt the process ... ISO is an engineering old boys club and these things are boring so you have to have a lot of passion … then suddenly you have an investment of a lot of money and lobbying and you get artificial results. The process is not set up to deal with intensive corporate lobbying and so you end up with something being a standard that is not clear.

## References

* ↑ "Discover ISO – Meet ISO". ISO. © 2007. Retrieved 2007-09-07. {{cite web}}: Check date values in: |year= (help)
* ↑ "ISO's name". ISO. 2007. Retrieved 2007-09-07.
* ↑ "Discover ISO – ISO's name". ISO. 2007. Retrieved 2007-09-07.
* 1 2 3 4 5 The ISO directives are published in two distinct parts: * "ISO Directives, Part 2: Rules for the structure and drafting of International Standards. 5th Edition" (PDF). ISO/IEC. 2004. Archived from the original (pdf) on 2006-03-21. Retrieved 2007-09-07.
* ↑ ISO. "ISO/IEC Directives and ISO supplement". Retrieved 2010-01-01.
* 1 2 "About MPEG". chiariglione.org. Retrieved 2009-12-13.
* 1 2 ISO. "International harmonized stage codes". Retrieved 2009-12-31.
* 1 2 3 4 5 ISO. "Stages of the development of International Standards". Retrieved 2009-12-31.
* 1 2 "The ISO27k FAQ - ISO/IEC acronyms and committees". IsecT Ltd. Retrieved 2009-12-31.
* ↑ ISO (2007). "ISO/IEC Directives Supplement — Procedures specific to ISO" (PDF). Retrieved 2009-12-31.
* ↑ ISO (2007). "List of abbreviations used throughout ISO Online". Retrieved 2009-12-31.
* 1 2 "US TAG COMMITTEE HANDBOOK" (DOC). 2008-03. Retrieved 2010-01-01. {{cite web}}: Check date values in: |date= (help)
* 1 2 ISO (2008), ISO/IEC Directives, Part 1 - Procedures for the technical work, Sixth edition, 2008 (PDF), archived from the original (PDF) on 2010-07-14, retrieved 2010-01-01
* ↑ ISO, IEC (2009-11-05). "ISO/IEC JTC 1/SC 29, SC 29/WG 11 Structure (ISO/IEC JTC 1/SC 29/WG 11 - Coding of Moving Pictures and Audio)". Retrieved 2009-11-07.
* ↑ ISO/IEC JTC1 (2009-11-02), Letter Ballot on the JTC 1 Standing Document on Technical Specifications and Technical Reports (PDF), retrieved 2010-01-01
* ↑ "Freely Available ISO Standards". ISO. Last updated 2007-08-08. Retrieved 2007-09-07. {{cite web}}: Check date values in: |year= (help)
* ↑ "Free ANSI Standards". Retrieved 2007-06-19.
* ↑ "General information on ISO". ISO. © 2009. Retrieved 2009-01-29. {{cite web}}: Check date values in: |year= (help)
* ↑ "ISO/IEC/JTC 2 - Joint Project Committee - Energy efficiency and renewable energy sources - Common terminology". Retrieved 2010-01-01.
* ↑ "Freely Available Standards". ISO. Retrieved 2008-04-26.
* ↑ "Shopping FAQs". ISO. Retrieved 2008-04-26.
* ↑ Jelliffe, Rick (2007-08-01). "Where to get ISO Standards on the Internet free". oreillynet.com. Retrieved 2008-04-26. The lack of free online availability has effectively made ISO standard irrelevant to the (home/hacker section of the) Open Source community
* ↑ "Report on WG1 activity for December 2007 Meeting of ISO/IEC JTC1/SC34/WG1 in Kyoto". iso/jtc1 sc34. 2007-11-29.
* ↑ "Ubuntu's Shuttleworth blames ISO for OOXML's win". ZDNet.com. 2008-04-01.

## External links

* ISO's official website (free access to the catalogue of standards only, not to the contents)
* Publicly Available Standards (free access to a small subset of the standards)
* ISO/TC 37 "Terminology and other language and content resources", a fundamental committee for all ISO standardization projects
* ISO/IEC JTC1
* ISO Advanced search for standards and/or projects

## Reference

* ,ISO