Active cables are copper cables used for data transmission that use an electronic circuit to boost their performance. Without an electronic circuit, a cable is considered passive. Unlike passive cables, which can suffer from data degradation due to issues such as attenuation, crosstalk, and group velocity distortion, active cables contain one or more integrated circuits to address these problems. This active boosting allows cables to be more compact, thinner, and longer, and to transmit data faster than passive cables.
Active cables are used in enterprise networks to connect consumer devices such as cameras, gaming consoles, and HDTVs.
Embedding circuitry in cables can allow less copper to be used in cable production while retaining performance. This reduces weight and offers longer reach and lower power consumption. [1] [2] Active cables use one or more integrated circuits to boost the signal passing through the cable. This helps to compensate for issues that can degrade data, such as attenuation, crosstalk, and group velocity distortion. There are two main types of active cables: Active Electrical Cables (AECs) and Active Optical Cables (AOCs). Both types have pluggable transceivers that are permanently connected to multiple strands of copper or fiber cable. Passive cables are copper cables that do not have an electronic circuit, and are prone to data degradation. Passive cables are also typically bi-directional, while active cables that convert a signal usually only work in one direction. There are two main types of signal conditioning used in active electrical cables: re-driver-based and re-timer. Re-driver-based AECs use a simpler signal amplification, while re-timer AECs use a clock and data recovery (CDR) based signal conditioning.
Active cables are used with products such as smartphones, HDTVs, gaming consoles, and DV cameras. DisplayPort is the latest consumer electronics standard to support active cables by allocating power supply pins inside the connector. Enabling ultra-thin (32 AWG and thinner) and long-reach interconnects which are particularly valuable for the use with the miniature Mini DisplayPort form factor. [3]
Active cables are used in enterprise and storage applications, where space and air-flow requirements in data centers are considerations. The thinner gauge of active cables allows for a tighter bend radius, which helps facilitate cable management and airflow.
As of 2010, half of the SFP+ interconnect volume are active cables (as opposed to passive copper cables and optical transceiver modules). [4] In addition to this, the advent of QSFP (Quad SFP) interconnects for 40 Gigabit Ethernet and InfiniBand has led to increased use of active cables in this form factor.
Some critics of active cable technology criticize the fact that the electronics in an active cable design could be placed inside the connected devices instead, and an inexpensive passive cable used to connect the devices. Digital alternatives to using analogue equalizers and impedance-matching circuits to improve cable performance also exist, such as channel estimation or link adaptation.
Another criticism of active cables is that manufacturers may patent the electronics inside an active cable or even utilize on-chip cryptography to prevent competitors or consumers from producing their replacement cables, and therefore enable manufacturers to monopolize the market for cables and charge consumers higher prices. Active cables are typically priced 5 to 10 times higher than passive cables. [12] Some active cables are only produced by a single manufacturer and sold through a single distributor.
Some critics argue that active cables do not provide power savings for signal processing reasons; in an active cable design, there is at least one extra integrated circuit (IC) compared to passive cable designs. This extra IC must be powered separately when, in a passive cable design, the signal processing can be integrated onto a single chip. [13]
In computer networking, Fast Ethernet physical layers carry traffic at the nominal rate of 100 Mbit/s. The prior Ethernet speed was 10 Mbit/s. Of the Fast Ethernet physical layers, 100BASE-TX is by far the most common.
In computer networking, Gigabit Ethernet is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in 1999, and has replaced Fast Ethernet in wired local networks due to its considerable speed improvement over Fast Ethernet, as well as its use of cables and equipment that are widely available, economical, and similar to previous standards. The first standard for faster 10 Gigabit Ethernet was approved in 2002.
In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequencies to transmit on, the line code to use and similar low-level parameters, are specified by the physical layer.
InfiniBand (IB) is a computer networking communications standard used in high-performance computing that features very high throughput and very low latency. It is used for data interconnect both among and within computers. InfiniBand is also used as either a direct or switched interconnect between servers and storage systems, as well as an interconnect between storage systems. It is designed to be scalable and uses a switched fabric network topology. Between 2014 and June 2016, it was the most commonly used interconnect in the TOP500 list of supercomputers.
PCI Express, officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common motherboard interface for personal computers' graphics cards, capture cards, sound cards, hard disk drive host adapters, SSDs, Wi-Fi, and Ethernet hardware connections. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism, and native hot-swap functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization.
Fibre Channel (FC) is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to servers in storage area networks (SAN) in commercial data centers.
In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels.
High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards.
Small Form-factor Pluggable (SFP) is a compact, hot-pluggable network interface module format used for both telecommunication and data communications applications. An SFP interface on networking hardware is a modular slot for a media-specific transceiver, such as for a fiber-optic cable or a copper cable. The advantage of using SFPs compared to fixed interfaces is that individual ports can be equipped with different types of transceivers as required, with the majority including optical line terminals, network cards, switches and routers.
A parallel optical interface is a form of fiber-optic technology aimed primarily at communications and networking over relatively short distances, and at high bandwidths.
An optical link is a telecommunications link that consists of a single end-to-end optical circuit. A cable of optical fibers, possibly concatenated into a dark fiber link, is the simplest form of an optical link.
Mobile High-Definition Link (MHL) is an industry standard for a mobile audio/video interface that allows the connection of smartphones, tablets, and other portable consumer electronics devices to high-definition televisions (HDTVs), audio receivers, and projectors. The standard was designed to share existing mobile device connectors, such as Micro-USB, and avoid the need to add video connectors on devices with limited space for them.
Audio connectors and video connectors are electrical or optical connectors for carrying audio or video signals. Audio interfaces or video interfaces define physical parameters and interpretation of signals. For digital audio and digital video, this can be thought of as defining the physical layer, data link layer, and most or all of the application layer. For analog audio and analog video these functions are all represented in a single signal specification like NTSC or the direct speaker-driving signal of analog audio.
IPtronics was a fabless semiconductor company headquartered in Copenhagen, Denmark. Its products include integrated circuits for parallel optical interconnect applications intended for the computer, storage and communication industries. IPtronics' design center is certified by STMicroelectronics, which is also their semiconductor foundry partner. In June 2013, IPtronics was acquired by Mellanox Technologies.
10 Gigabit Ethernet is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE 802.3ae-2002 standard. Unlike previous Ethernet standards, 10GbE defines only full-duplex point-to-point links which are generally connected by network switches; shared-medium CSMA/CD operation has not been carried over from the previous generations of Ethernet standards so half-duplex operation and repeater hubs do not exist in 10GbE. The first standard for faster 100 Gigabit Ethernet links was approved in 2010.
Thunderbolt is the brand name of a hardware interface for the connection of external peripherals to a computer. It was developed by Intel in collaboration with Apple. It was initially marketed under the name Light Peak, and first sold as part of an end-user product on 24 February 2011.
USB-C, or USB Type-C, is a 24-pin connector that supersedes previous USB connectors and can carry audio, video, and other data, to connect to monitors or external drives. It can also provide and receive power, to power, e.g., a laptop or a mobile phone. It is used not only by USB technology, but also by other protocols, including Thunderbolt, PCIe, HDMI, DisplayPort, and others. It is extensible to support future protocols.
Fiber to the office (FTTO) is an alternative cabling concept for local area network (LAN) network office environments. It combines passive elements and active mini-switches to provide end devices with Gigabit Ethernet. FTTO involves centralised optical fibre cabling techniques to create a combined backbone/horizontal channel; this channel is provided from the work areas to the centralised cross-connect or interconnect by allowing the use of pull-through cables or splices in the telecommunications room.
An optical module is a typically hot-pluggable optical transceiver used in high-bandwidth data communications applications. Optical modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the side that connects to the outside world through a fiber optic cable. The form factor and electrical interface are often specified by an interested group using a multi-source agreement (MSA). Optical modules can either plug into a front panel socket or an on-board socket. Sometimes the optical module is replaced by an electrical interface module that implements either an active or passive electrical connection to the outside world. A large industry supports the manufacturing and use of optical modules.