Active Cables
Encyclopedia
Active cables are copper
cables for data transmission that use a silicon chip (semiconductor
) to boost the performance of the cable. Without a chip
, a cable is considered a 'passive' cable. Passive cables are liable to degrade the data they carry, due to such "channel impairments" as attenuation
, crosstalk and group velocity distortion. In active cables, one or several semiconductor chips are embedded in the cable to compensate for some or all of these impairments. This active boosting allows cables to be more compact, thinner, longer and transmit data faster than their passive equivalents.
Today, active cables are used to connect consumer
devices such as camera
s, gaming consoles and HDTVs, as well as enterprise networks which form the backbone of modern data communication systems.
The major benefit of embedding chip technology in cables is a reduction in the copper used in cable production, reducing the overall form factor of the cable and reducing the weight of the cable by as much as 80%. Other benefits include longer reach and lower power consumption: active cables have demonstrated reach extensions up to 5× over simple passive cables while consuming approximately 75% less power than comparable fiber-based interconnects.
trends are leaning towards miniaturization and connectivity. Because active cables are more compact and portable than passive cables, they are ideal for use with products such as smartphones, HDTVs, gaming consoles and DV cameras. DisplayPort
is the latest consumer electronics standard that has enabled support for active cables by allocating power supply pins inside the connector. Active DisplayPort cables enable ultra-thin (32 AWG
and thinner) and long-reach interconnects which are particularly valuable for the use with the miniature mini DisplayPort
form-factor.
Active cable adoption in data centers has been growing steadily. For example, as of 2010, half of SFP+ interconnect volume is in active cables (as opposed to passive copper cables and optical transceiver modules). The advent of QSFP (Quad SFP) interconnects for 40 Gigabit Ethernet and Infiniband
is driving the widespread adoption of active cables in this form-factor as well.
and de-skew, both forms of filtering and amplification which is applied to the signal before it leaves the connector at the end of the cable. In some cases, chips are used at both ends of an active cable where the first device actively boosts the signal before it is transmitted over the copper lines and the second chip improves the signal integrity before it leaves the end connector.
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
cables for data transmission that use a silicon chip (semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
) to boost the performance of the cable. Without a chip
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
, a cable is considered a 'passive' cable. Passive cables are liable to degrade the data they carry, due to such "channel impairments" as attenuation
Attenuation
In physics, attenuation is the gradual loss in intensity of any kind of flux through a medium. For instance, sunlight is attenuated by dark glasses, X-rays are attenuated by lead, and light and sound are attenuated by water.In electrical engineering and telecommunications, attenuation affects the...
, crosstalk and group velocity distortion. In active cables, one or several semiconductor chips are embedded in the cable to compensate for some or all of these impairments. This active boosting allows cables to be more compact, thinner, longer and transmit data faster than their passive equivalents.
Today, active cables are used to connect consumer
Consumer
Consumer is a broad label for any individuals or households that use goods generated within the economy. The concept of a consumer occurs in different contexts, so that the usage and significance of the term may vary.-Economics and marketing:...
devices such as camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
s, gaming consoles and HDTVs, as well as enterprise networks which form the backbone of modern data communication systems.
The major benefit of embedding chip technology in cables is a reduction in the copper used in cable production, reducing the overall form factor of the cable and reducing the weight of the cable by as much as 80%. Other benefits include longer reach and lower power consumption: active cables have demonstrated reach extensions up to 5× over simple passive cables while consuming approximately 75% less power than comparable fiber-based interconnects.
Consumer electronics
Consumer electronicsConsumer electronics
Consumer electronics are electronic equipment intended for everyday use, most often in entertainment, communications and office productivity. Radio broadcasting in the early 20th century brought the first major consumer product, the broadcast receiver...
trends are leaning towards miniaturization and connectivity. Because active cables are more compact and portable than passive cables, they are ideal for use with products such as smartphones, HDTVs, gaming consoles and DV cameras. DisplayPort
DisplayPort
DisplayPort is a digital display interface standard produced by the Video Electronics Standards Association . The specification defines a royalty-free digital interconnect for audio and video. The interface is primarily used to connect a video source to a display device such as a computer monitor...
is the latest consumer electronics standard that has enabled support for active cables by allocating power supply pins inside the connector. Active DisplayPort cables enable ultra-thin (32 AWG
AWG
AWG may refer to:In science and technology:* American wire gauge, a standardized sizing system for electrically conducting wire* Arbitrary waveform generator, a piece of electronic test equipment used to generate electrical waveforms...
and thinner) and long-reach interconnects which are particularly valuable for the use with the miniature mini DisplayPort
Mini DisplayPort
The Mini DisplayPort is a miniaturized version of the DisplayPort digital audio-visual interface. Apple, Inc. announced the development in the fourth quarter of 2008, and now applies it in the LED Cinema Display and in all new Macintosh computers: MacBook, MacBook Pro, MacBook Air, iMac, Mac mini,...
form-factor.
Enterprise and storage applications
Active cables play an important role in enterprise and storage applications due to the confined space and air-flow requirements in data centers and long reaches (up to 30 meters) required to make some of the rack-to-rack connections. Because active cables can facilitate thin cable gauges, a tighter bend radius results, which can give cables in these applications better routability and improved airflow.Active cable adoption in data centers has been growing steadily. For example, as of 2010, half of SFP+ interconnect volume is in active cables (as opposed to passive copper cables and optical transceiver modules). The advent of QSFP (Quad SFP) interconnects for 40 Gigabit Ethernet and Infiniband
InfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
is driving the widespread adoption of active cables in this form-factor as well.
Standards
Benefits
Active cables offer benefits over their passive equivalents:- Cables support much longer reach
- Cables become thinner, lighter, more flexible and more compact
- Cables have a tighter bend radius
- Cables can be more easily routed
- Cable conduits are smaller, allowing for better air flow
- An overall improvement in signal integrity
- Cables require less signal processing by the host system, leading to savings in power consumption, cost, etc
Technology
The active component in active cables is a semiconductor device which acts to boost the quality of the data signal. The most common technology used is equalizationEqualization
Equalization, is the process of adjusting the balance between frequency components within an electronic signal. The most well known use of equalization is in sound recording and reproduction but there are many other applications in electronics and telecommunications. The circuit or equipment used...
and de-skew, both forms of filtering and amplification which is applied to the signal before it leaves the connector at the end of the cable. In some cases, chips are used at both ends of an active cable where the first device actively boosts the signal before it is transmitted over the copper lines and the second chip improves the signal integrity before it leaves the end connector.
See also
- Light PeakLight PeakThunderbolt is an interface for connecting peripheral devices to a computer via an expansion bus. Thunderbolt was developed by Intel and brought to market with technical collaboration from Apple Inc. It was introduced commercially on Apple's updated MacBook Pro lineup on February 24, 2011, using...
- Optical interconnectOptical interconnectOptical interconnect is a way of communication by optical cables. Compared to traditional cables, optical wires are capable of a much higher bandwidth, from 10 Gb/s up to 100 Gb/s....
- Parallel optical interfaceParallel optical interfaceA parallel optical interface is a form of fiber optic technology aimed primarily at communications and networking over relatively short distances , and at high bandwidths....
- Interconnect bottleneckInterconnect bottleneckThe interconnect bottleneck, the point at which integrated circuits reach their capacity, is expected sometime around 2010.Improved performance of computer systems has been achieved, in large part, by downscaling the IC minimum feature size. This allows the basic IC building block, the transistor,...
- Optical communicationOptical communicationOptical communication is any form of telecommunication that uses light as the transmission medium.An optical communication system consists of a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the...
- Optical cable
- Green computingGreen computingGreen computing or green IT, refers to environmentally sustainable computing or IT. In the article Harnessing Green IT: Principles and Practices, San Murugesan defines the field of green computing as "the study and practice of designing, manufacturing, using, and disposing of computers, servers,...
- InfiniBandInfiniBandInfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...
- Fibre channelFibre ChannelFibre Channel, or FC, is a gigabit-speed network technology primarily used for storage networking. Fibre Channel is standardized in the T11 Technical Committee of the InterNational Committee for Information Technology Standards , an American National Standards Institute –accredited standards...
- HDMIHDMIHDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
- PCI ExpressPCI ExpressPCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
- Small form-factor pluggable transceiver
- Terabit EthernetTerabit EthernetTerabit Ethernet or 1TbE is a phrase used in current media to describe the next possible speed of Ethernet above 100 Gigabit Ethernet speeds. Facebook, and Google are a few companies that have expressed a need for 1TbE...
- 100 Gigabit Ethernet100 Gigabit Ethernet40 Gigabit Ethernet, or 40GbE, and 100 Gigabit Ethernet, or 100GbE, are high-speed computer network standards developed by the Institute of Electrical and Electronics Engineers . They support sending Ethernet frames at 40 and 100 gigabits per second over multiple 10 Gbit/s or 25 Gbit/s lanes...
- 10 Gigabit Ethernet10 Gigabit EthernetThe 10 gigabit Ethernet computer networking standard was first published in 2002. It defines a version of Ethernet with a nominal data rate of 10 Gbit/s , ten times faster than gigabit Ethernet.10 gigabit Ethernet defines only full duplex point to point links which are generally connected by...
- OptoelectronicsOptoelectronicsOptoelectronics is the study and application of electronic devices that source, detect and control light, usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light...
- Data centerData centerA data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...
- High-performance computingHigh-performance computingHigh-performance computing uses supercomputers and computer clusters to solve advanced computation problems. Today, computer systems approaching the teraflops-region are counted as HPC-computers.-Overview:...
- Cloud computingCloud computingCloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a utility over a network ....
- CXP (connector)CXP (connector)In the field of computer networking, CXP is a copper connector system with twelve 10 Gbit/s links suitable for 100 Gigabit Ethernet, three 40 Gigabit Ethernet channels, or twelve 10 Gigabit Ethernet channels. or a single Infiniband 12× QDR link. The C is the Roman numeral for 100 as a memory...
- C Form-factor PluggableC Form-factor PluggableThe C form-factor pluggable is a multi-source agreement to produce a common form-factor for the transmission high-speed digital signals...
- Fiber-optic communicationFiber-optic communicationFiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information...
- Optical linkOptical linkAn optical link is a communications link that consists of a single end-to-end optical circuit. A cable of optical fiber, possibly concatenated into a dark fiber link, is the simplest form of an optical link....
- List of device bandwidths