In
telecommunications
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
, data-transfer rate is the average number of
bit
The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represente ...
s (
bitrate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...
), characters or symbols (
baudrate
In telecommunication and electronics, baud (; symbol: Bd) is a common unit of measurement of symbol rate, which is one of the components that determine the speed of communication over a data channel.
It is the unit for symbol rate or modul ...
), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multiples of
bits per second
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...
(bit/s) and
bytes per second (B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s).
Standards for unit symbols and prefixes
Unit symbol
The
ISQ symbols for the bit and byte are ''bit'' and ''B'', respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unit
octet
Octet may refer to:
Music
* Octet (music), ensemble consisting of eight instruments or voices, or composition written for such an ensemble
** String octet, a piece of music written for eight string instruments
*** Octet (Mendelssohn), 1825 compos ...
. The abbreviation bps is often used to mean bit/s, so that when a ''1 Mbps'' connection is advertised, it usually means that the maximum achievable bandwidth is 1 Mbit/s (one million bits per second), which is 0.125 MB/s (
megabyte per second
In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols ( baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are mul ...
), or about 0.1192 MiB/s (
mebibyte per second
In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multi ...
). The
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
(IEEE) uses the symbol b for bit.
Unit prefixes
In both the
SI and ISQ, the prefix k stands for
kilo
KILO (94.3 FM broadcasting, FM, 94.3 KILO) is a radio station broadcasting in Colorado Springs, Colorado, Colorado Springs and Pueblo, Colorado, Pueblo, Colorado. It also streams online.
History
KLST and KPIK-FM
The 94.3 signal signed on th ...
, meaning 1,000, while Ki is the symbol for the
binary prefix
A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...
kibi-
A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...
, meaning 1,024. The binary prefixes were introduced in 1998 by the
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
(IEC) and in
IEEE 1541-2002 which was reaffirmed on 27 March 2008. The letter K is often used as a non-standard abbreviation for 1,024, especially in "KB" to mean KiB, the
kilobyte in its binary sense. In the context of data rates, however, typically only decimal prefixes are used, and they have their standard SI interpretation.
Variations
In 1999, the IEC published Amendment 2 to "
IEC 60027-2
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and ...
: Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics". This standard, approved in 1998, introduced the prefixes kibi-, mebi-, gibi-, tebi-, pebi-, and exbi- to be used in specifying binary multiples of a quantity. The name is derived from the first two letters of the original SI prefixes followed by bi (short for ''binary''). It also clarifies that the SI prefixes are used only to mean powers of 10 and never powers of 2.
Decimal multiples of bits
These units are often used in a manner inconsistent with the IEC standard.
Kilobit per second
Kilobit per second (symbol kbit/s or kb/s, often abbreviated "kbps") is a unit of data transfer rate equal to:
* 1,000 bits per second
* 125 bytes per second
Megabit per second
Megabit per second (symbol Mbit/s or Mb/s, often abbreviated "Mbps") is a unit of data transfer rate equal to:
* 1,000 kilobits per second
* 1,000,000 bits per second
* 125,000 bytes per second
* 125 kilobytes per second
Gigabit per second
Gigabit per second (symbol Gbit/s or Gb/s, often abbreviated "Gbps") is a unit of data transfer rate equal to:
* 1,000 megabits per second
* 1,000,000 kilobits per second
* 1,000,000,000 bits per second
* 125,000,000 bytes per second
* 125 megabytes per second
Terabit per second
Terabit per second (symbol Tbit/s or Tb/s, sometimes abbreviated "Tbps") is a unit of data transfer rate equal to:
* 1,000 gigabits per second
* 1,000,000 megabits per second
* 1,000,000,000 kilobits per second
* 1,000,000,000,000 bits per second
* 125,000,000,000 bytes per second
* 125 gigabytes per second
Decimal multiples of bytes
These units are often not used in the suggested ways; see above section titled "
variations
Variation or Variations may refer to:
Science and mathematics
* Variation (astronomy), any perturbation of the mean motion or orbit of a planet or satellite, particularly of the moon
* Genetic variation, the difference in DNA among individua ...
".
Kilobyte per second
kilobyte per second (kB/s) (can be abbreviated as kBps) is a unit of data transfer rate equal to:
* 8,000 bits per second
* 1,000 bytes per second
* 8 kilobits per second
Megabyte per second
megabyte per second (MB/s) (can be abbreviated as MBps) is a unit of data transfer rate equal to:
* 8,000,000 bits per second
* 1,000,000 bytes per second
* 1,000 kilobytes per second
* 8 megabits per second
Gigabyte per second
gigabyte per second (GB/s) (can be abbreviated as GBps) is a unit of data transfer rate equal to:
* 8,000,000,000 bits per second
* 1,000,000,000 bytes per second
* 1,000,000 kilobytes per second
* 1,000 megabytes per second
* 8 gigabits per second
Terabyte per second
terabyte per second (TB/s) (can be abbreviated as TBps) is a unit of data transfer rate equal to:
* 8,000,000,000,000 bits per second
* 1,000,000,000,000 bytes per second
* 1,000,000,000 kilobytes per second
* 1,000,000 megabytes per second
* 1,000 gigabytes per second
* 8 terabits per second
Conversion table
Examples of bit rates
See also
*
Binary prefix
A binary prefix is a unit prefix for multiples of units. It is most often used in data processing, data transmission, and digital information, principally in association with the bit and the byte, to indicate multiplication by a power of& ...
*
Bit rate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...
*
List of interface bit rates
*
Orders of magnitude (bit rate)
*
Orders of magnitude (data)
An order of magnitude is usually a factor of ten. Thus, four orders of magnitude is a factor of 10,000 or 104.
This article presents a list of multiples, sorted by orders of magnitude, for units of information measured in bits and bytes.
The byt ...
*
Metric prefix
A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The pre ...
*
Instructions per second
Instructions per second (IPS) is a measure of a computer's processor speed. For complex instruction set computers (CISCs), different instructions take different amounts of time, so the value measured depends on the instruction mix; even for compa ...
Notes
References
* International Electrotechnical Commission (2007).
Prefixes for binary multiples (archived). Retrieved on 2007-05-06.
lacks table but now references IEC 80000-13:2008 rather than IEC 60027-2.
IEC 60027-2 "Letter symbols to be used in electrical technology – Part 2: Telecommunications and electronics+*
Donald Knuth
Donald Ervin Knuth ( ; born January 10, 1938) is an American computer scientist, mathematician, and professor emeritus at Stanford University. He is the 1974 recipient of the ACM Turing Award, informally considered the Nobel Prize of computer sc ...
"What is a kilobyte?"
External links
Valid8 Data Rate Calculator
{{DEFAULTSORT:Data Rate Units
Data transmission
Units of flow
Units of information
Units of temporal rate