Digital Electronics/Printable version

Digital Electronics

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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 2ⁿ 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.

$1A=1*16^{1}+10*16^{0}=26$

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.

Solderless breadboard with 400 connection points

They typically come in three sizes

• mini
• half (around 400 connection points)
• full

Logic Gates

Family Logic Gates

1. Fundamental Digital Gates
2. Combinational Gates
3. Basic Logic Gates Summary
4. 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 Gates	Symbol	Mathmatical Formula	Truth Table
Buffer		Q = A	A Q 0 0 1 1
NOT		Q = NOT A	A Q 0 1 1 0
AND		Q = A . B	A B Q 0 0 0 0 1 0 1 0 0 1 1 1
OR		Q = A + B	A B Q 0 0 0 0 1 1 1 0 1 1 1 1
XOR		Q = A (+) B	A B Q 0 0 0 0 1 1 1 0 1 1 1 0

Logic Gates/Combinational Gates

Combination gates

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

Buffer

Basic Logic Gates	Combinational Gates	Symbol	Mathmatical Formula	Truth Table
Buffer			Y = is NOT NOT A Y = A	A Q 0 0 1 1

NOT Gate

Digital Gate	Combinational Gates	Symbol	Mathematical Expression	Truth Table
NOT Gate			Y = is NOT A	A Y 0 1 1 0

NAND Gate

Digital Gate	Combinational Gate	Symbol	Mathematical Expression	Truth Table
Buffer			Y = is NOT A.B	A B Y 0 0 1 0 1 1 1 0 1 1 1 0

NOR Gate

Digital Gate	Combinational Gate	Symbol	Mathematical Expression	Truth Table
NOT			Y = is NOT A+B	A B Y 0 0 1 0 1 0 1 0 0 1 1 0

XNOR Gate

Basic Gates	Combinational Gate	Symbol	Mathematical Formula	Truth Table
NOT Gate			Y = is NOT AxorB	A 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 Gates	Symbol	Mathmatical Formula	Truth Table
Buffer		Q = A	A Q 0 0 1 1
NOT		Q = NOT A	A Q 0 1 1 0
AND		Q = A . B	A B Q 0 0 0 0 1 0 1 0 0 1 1 1
NAND		Q = NOT (A . B)	A B Q 0 0 1 0 1 1 1 0 1 1 1 0
OR		Q = A + B	A B Q 0 0 0 0 1 1 1 0 1 1 1 1
NOR		Q = NOT (A + B)	A B Q 0 0 1 0 1 0 1 0 0 1 1 0
XOR		Q = (A + B) . NOT (A . B)	A B Q 0 0 0 0 1 1 1 0 1 1 1 0
XNOR		Q = 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 Gates	Symbol	Mathmatical Formula	Truth Table	Constructions
Buffer		Q = A	A Q 0 0 1 1
NOT		Q = NOT A	A Q 0 1 1 0
AND		Q = A . B	A B Q 0 0 0 0 1 0 1 0 0 1 1 1
NAND		Q =NOT (A . B)	A B Q 0 0 1 0 1 1 1 0 1 1 1 0
OR		Q = A + B	A B Q 0 0 0 0 1 1 1 0 1 1 1 1
NOR		Q = NOT (A + B)	A B Q 0 0 1 0 1 0 1 0 0 1 1 0
XOR		Q = A + B	A B Q 0 0 0 0 1 1 1 0 1 1 1 0
XNOR		Q = A + B	A B Q 0 0 0 0 1 1 1 0 1 1 1 1

Mathematic and Logic Operations

1. Digital Adder
2. Digital Subtractor
3. Digital Decoder
4. Digital Encoder

Synchronous Device

Synchronous Device

1. Flip Flop
2. Register
3. Counter

Asychronous Device

Asychronous Device

1. Digital Multiplexer
2. Digital DeMultiplexing

Digital Data

Digital Data

Digital Data is a Binary Numbers of two bits 0 and 1 . A 0 & 1 could be

1. 0v & 5v
2. Switch Opened & Switch Closed
3. 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 a₃a₂a₁a₀ which can be used to represent a number of base ten from 0 to 3

A	B	a3	a2	a1	a0	Decimal Number
0	0	0	0	0	0	0
0	1	0	0	0	1	1
1	0	0	0	1	0	2
1	1	0	0	1	1	3

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

A	B	a3	a2	a1	a0	Decimal Number
0	0	0	0	0	0	0
0	1	0	0	0	1	1
1	0	0	0	1	0	2
1	1	0	0	1	1	3
1	1	0	1	0	0	4
1	1	0	1	0	1	5
1	1	0	1	1	0	6
1	1	0	1	1	1	7
1	1	1	0	0	0	8
1	1	1	0	0	1	9

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

1. Number from 0 to 9
2. Capital A to Z
3. 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.

Binary	Oct	Dec	Hex	Glyph
010 0000	040	32	20	space
010 0001	041	33	21	!
010 0010	042	34	22	"
010 0011	043	35	23	#
010 0100	044	36	24	$
010 0101	045	37	25	%
010 0110	046	38	26	&
010 0111	047	39	27	'
010 1000	050	40	28	(
010 1001	051	41	29	)
010 1010	052	42	2A	*
010 1011	053	43	2B	+
010 1100	054	44	2C	,
010 1101	055	45	2D	-
010 1110	056	46	2E	.
010 1111	057	47	2F	/
011 0000	060	48	30	0
011 0001	061	49	31	1
011 0010	062	50	32	2
011 0011	063	51	33	3
011 0100	064	52	34	4
011 0101	065	53	35	5
011 0110	066	54	36	6
011 0111	067	55	37	7
011 1000	070	56	38	8
011 1001	071	57	39	9
011 1010	072	58	3A	:
011 1011	073	59	3B	;
011 1100	074	60	3C	<
011 1101	075	61	3D	=
011 1110	076	62	3E	>
011 1111	077	63	3F	?

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.

Example: A Single Bit 1-to-4 Line Demultiplexer

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

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

A map of standards bodies who are ISO members
Key:
     members      correspondent members      subscriber members      other places with an ISO 3166-1 code who aren't members of ISO

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

Main article: ISO/IEC JTC1

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.

See also

• American National Standards Institute (ANSI)
• Deutsches Institut für Normung, German Institute for Standardization (DIN)
• British Standards Institution (BSI)
• Countries in International Organization for Standardization
• Canadian Standards Association
• European Committee for Standardization (CEN)
• Commonwealth of Independent States (CIS) set of standards (GOST)
• International Classification for Standards
• International Electrotechnical Commission (IEC) and ISO/IEC standards
• International healthcare accreditation
• International Telecommunication Union (ITU)
• ISO A4
• ISO country code
• List of ISO standards

• ISO divisions
  • ISO/TC 37
  • ISO/TC 68
  • TC 46/SC 9
  • ISO/TC 211
  • ISO/TC 215
  • ISO/TC 223
• Standardization
• Standards Australia
• Standards organization
• Terminology planning policy
• The International Customer Service Institute (TICSI)
• CARICOM Regional Organisation for Standards and Quality (CROSQ)
• AP Stylebook (Associated Press Style)
• Interface 2010 (Interface Marketing Supplier Integration Institute)

References

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

• [1] ,ISO