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45-470: It can use twisted pair (in a tree , line or star topology ), powerline , RF , or IP links. On this network, the devices form distributed applications and tight interaction is possible. This is implemented via interworking models with standardised datapoint types and objects , modelling logical device channels. The KNX standard has been built on the OSI -based EIB communication stack extended with

90-407: A balanced line , which as part of a balanced circuit can greatly reduce the effect of noise currents induced on the line by coupling of electric or magnetic fields. The idea is that the currents induced in each of the two wires are very nearly equal. The twisting ensures that the two wires are on average the same distance from the interfering source and are affected equally. The noise thus produces

135-435: A common-mode signal which can be cancelled at the receiver by detecting the difference signal only, the latter being the wanted signal. Common-mode rejection starts to fail on untwisted wires when the noise source is close to the signal wires; the closer wire will couple with the noise more strongly and the receiver will be unable to eliminate it. This problem is especially apparent in telecommunication cables where pairs in

180-493: A single conductor or an untwisted balanced pair , a twisted pair reduces electromagnetic radiation from the pair and crosstalk between neighbouring pairs and improves rejection of external electromagnetic interference . It was invented by Alexander Graham Bell . For additional noise immunity, twisted-pair cabling may be shielded . Cable with shielding is known as shielded twisted pair ( STP ) and without as unshielded twisted pair ( UTP ). A twisted pair can be used as

225-402: A four-pair cable, there would be a total of eight solid wires. Stranded cable uses multiple wires wrapped around each other in each conductor and in a four-pair with seven strands per conductor cable, there would be a total of 56 wires (2 per pair × 4 pairs × 7 strands). Solid core cable is intended for permanently installed runs ( permanent link ). It is less flexible than stranded cable and

270-405: A resin to prevent the ingress of moisture which would seriously degrade the insulating properties of the paper insulation. However, such seals made future maintenance and changes more difficult. These cables are no longer made but are still occasionally encountered in old buildings and in various external areas, commonly rural villages. A loaded twisted pair has intentionally added inductance and

315-470: A set of devices connected to the bus or network. Device models vary according to node roles, capabilities, management features and configuration modes, and are all laid down in the profiles . There are also general-purpose device models, such as for bus coupling units (BCUs) or bus interface modules (BIMs). Devices may be identified and subsequently accessed throughout the network either by their individual address, or by their unique serial number, depending on

360-543: A signaling speed of 9600 bit/s. Media access control is via CSMA/CA . Every bus user has equal data transmission rights and data is exchanged directly (peer-to-peer) between bus users. SELV power is distributed via the same pair for low-power devices. A deprecated specification, TP0, running at a slower signalling speed of 4800 bit/s , has been retained from the BatiBUS standard but KNX products cannot exchange information with BatiBUS devices. PL 110 power-line transmission

405-438: A twist rate of about four twists per kilometre , or six per mile . Such open-wire balanced lines with periodic transpositions still survive today in some rural areas. Twisted-pair cabling was invented by Alexander Graham Bell in 1881. By 1900, the entire American telephone network was either twisted pair or open wire with transposition to guard against interference. Today, most of the millions of kilometres of twisted pairs in

450-424: Is a hybrid network topology in which star networks are interconnected via bus networks . Tree networks are hierarchical, and each node can have an arbitrary number of child nodes. A regular tree network's topology is characterized by two parameters: the branching, d {\displaystyle d} , and the number of generations, G {\displaystyle G} . The total number of

495-431: Is a precondition or “bootstrap” phase, prior to the configuration of the distributed applications, i.e. binding and parameter setting. Configuration may be achieved through a combination of local activity on the devices (such pushing a button), and active network management communication over the bus (peer-to-peer, or more centralized master-slave). The KNX configuration mode: Some modes require more active management over

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540-711: Is a royalty-free open standard and thus access to the KNX specifications is unrestricted. KNX devices are commonly connected by a twisted pair bus and can be modified from a controller. The bus is routed in parallel to the electrical power supply to all devices and systems on the network linking: Classifying devices as either "sensor" or "actuator" is outdated and simplistic. Many actuators include controller functionality, but also sensor functionality (for instance measuring operating hours, number of switch cycles, current, electrical power consumption, and more). Application software, together with system topology and commissioning software,

585-402: Is a variant of standard ribbon cable in which adjacent pairs of conductors are bonded and twisted together. The twisted pairs are then lightly bonded to each other in a ribbon format. Periodically along the ribbon, there are short sections with no twisting where connectors may be attached using the usual ribbon cable IDC techniques. A solid-core cable uses one solid wire per conductor and in

630-507: Is an approved standard by the following organisations, ( inter alia ): It is administered by the KNX Association cvba , a non-profit organisation governed by Belgian law which was formed in 1999. The KNX Association had 500 registered hardware and software vendor members from 45 nations as at 1 July 2021. It had partnership agreements with 100,000 installer companies in 172 countries and more than 500 registered training centres. This

675-475: Is delivered using spread frequency shift keying signalling with asynchronous transmission of data packets and half duplex bi-directional communication. It uses the central frequency 110 kHz (CENELEC B-band) and has a data rate of 1200 bit/s. It also uses CSMA. KNX Powerline is aimed at smart white goods , but the take-up has been low. An alternative variant, PL 132, has a carrier frequency centred on 132.5 kHz (CENELEC C-band). RF enables communication in

720-459: Is loaded onto the devices via a system interface component. Installed systems can be accessed via LAN, point to point links, or phone networks for central or distributed control of the system via computers, tablets and touch screens, and smartphones. The key features of the KNX architecture are: Central to the KNX architecture concepts are datapoints (inputs, outputs, parameters, and diagnostic data) which represent process and control variables in

765-636: Is more prone to failure if repeatedly flexed due to work hardening . Stranded cable is used at patch panels and for connections from wall ports to end devices ( patch cord or drop cable), as it resists cracking of the conductors. Connectors are designed differently for solid core than for stranded. Use of a connector with the wrong cable type can lead to unreliable cabling. Plugs designed for solid and stranded cores are readily available, and some vendors even offer plugs designed for use with both types. The punch-down blocks on patch-panel and wall-port jacks are designed for use with solid core cable. These work via

810-502: Is not surrounded by any shielding. UTP is the primary wire type for telephone usage and is very common for computer networking . The earliest telephones used telegraph lines which were single-wire earth return circuits. In the 1880s electric trams were installed in many cities, which induced noise into these circuits. In some countries, the tram companies were held responsible for disruption to existing telegraph lines and had to pay for remedial work. For new installations, however, it

855-527: Is recommended for a large installation. KNX can link up to 57,375 devices using 16-bit addresses. Coupling units allow address filtering which helps to improve performance given the limited bus signal speed. An installation based on KNXnet/IP allows the integration of KNX sub networks via IP as the KNX address structure is similar to an IP address. The TP1 twisted pair bus (inherited from EIB) provides asynchronous , character oriented data transfer and half-duplex bidirectional differential signaling with

900-492: The baseband of television signals, UTP is now used in some video applications, primarily in security cameras . As UTP is a balanced transmission line, a balun is needed to connect to unbalanced equipment, for example any using BNC connectors and designed for coaxial cable. Twisted pair cables may incorporate shielding in an attempt to prevent electromagnetic interference. Shielding provides an electrically conductive barrier to attenuate electromagnetic waves external to

945-486: The insulation-displacement method , whereby the device pierces the sides of the insulation and "bites" into the copper conductor to form a connection. Punchdown blocks are used as patch panels or as break-out boxes, for twisted pair cable. Twisted pair has the following useful attributes: Twisted pair has the following limitations: [REDACTED] Media related to Twisted-pair cables at Wikimedia Commons Tree network A tree topology , or star-bus topology ,

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990-418: The physical layers , configuration modes and application experience of BatiBUS and EHS . KNX installations can use several physical communication media: KNX is not based on a specific hardware platform and a network can be controlled by anything from an 8-bit microcontroller to a PC, according to the demands of a particular building. The most common form of installation is over twisted pair medium. KNX

1035-424: The 868.3 MHz band for using frequency shift keying with Manchester data encoding . KNXnet/IP port 3671 has integration solutions for IP -enabled media like Ethernet (IEEE 802.2), Bluetooth , WiFi/Wireless LAN (IEEE 802.11), FireWire (IEEE 1394) etc. Ignoring any preamble for medium-specific access and collision control, a frame format is generally: KNX Telegrams can be signed or encrypted thanks to

1080-414: The bus, whereas some others are mainly oriented towards local configuration. There are three categories of KNX devices: KNX encompasses tools for project engineering tasks such as linking a series of individual devices into a functioning installation and integrating different media and configuration modes. This is embodied in an Engineering Tool Software (ETS) suite. A KNX installation always consists of

1125-520: The cable. UTP is also the most common cable used in computer networking . Modern Ethernet , the most common data networking standard, can use UTP cables, with increasing data rates requiring higher specification variants of the UTP cable. Twisted-pair cabling is often used in data networks for short and medium-length connections because of its relatively lower costs compared to optical fibre and coaxial cable . As UTP cable bandwidth has improved to match

1170-504: The coloured insulation typically made from an insulator such as polyethylene or FEP and the total package covered in a polyethylene jacket. For urban outdoor telephone cables containing hundreds or thousands of pairs, the cable is divided into small but identical bundles. Each bundle consists of twisted pairs that have different twist rates, as pairs having the same twist rate within the cable can still experience some degree of crosstalk . The bundles are in turn twisted together to make up

1215-416: The common use of polyethylene and other plastics for insulation, telephone twisted pair cable was insulated with waxed paper or cotton with a wax coating applied to the copper. The overall sheath of this type of cable was usually lead. This style of cable came into use in the late 19th century shortly after the invention of the telephone. The cable termination in termination boxes were sealed with molten wax or

1260-506: The configuration mode. (Unique serial numbers are allocated by the KNX Association Certification Department.) Devices can also disclose both a manufacturer specific reference and functional (manufacturer independent) information when queried. A KNX wired network can be formed with tree , line and star topologies, which can be mixed as needed; ring topologies are not supported. A tree topology

1305-399: The extension of the protocol that was developed starting in 2013, KNX Data Secure for securing telegrams on the traditional KNX media TP and RF and KNX IP Secure for securing KNX telegrams tunnelled via IP. KNX Data Secure became an EN standard (EN 50090-3-4) in 2018, KNX IP Secure an ISO standard (ISO 22510) in 2019. Any product labeled with the KNX trademark must be certified to conform with

1350-425: The length of the cable. Pioneered by Belden , it is intended to help assure configuration consistency during and after installation. One key benefit is that the noise immunity performance of the cable can be protected despite potentially rough handling. The enhanced performance may be unnecessary and bonding reduces the flexibility of the cable and makes it prone to failure where it is flexed. A twisted ribbon cable

1395-479: The network, KNX has three underlying binding schemes: one for free, one for structured and one for tagged binding: The common kernel sits on top of the physical layers and the medium-specific data link layer and is shared by all the devices on the KNX Network. It is OSI 7-layer model compliant: An installation has to be configured at the network topology level and at individual nodes or devices. The first level

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1440-416: The nodes, N {\displaystyle N} , and the number of peripheral nodes N p {\displaystyle N_{p}} , are given by Three parameters are crucial in determining the statistics of random tree networks, first, the branching probability, second the maximum number of allowed progenies at each branching point, and third the maximum number of generations, that

1485-436: The route with electrical power lines . Within a few years, the growing use of electricity again brought an increase of interference, so engineers devised a method called wire transposition , to cancel out the interference. In wire transposition, the wires exchange position once every several poles. In this way, the two wires would receive similar EMI from power lines. This represented an early implementation of twisting, with

1530-417: The same cable lie next to each other for many miles. Twisting the pairs counters this effect as on each half twist the wire nearest to the noise source is exchanged. Provided the interfering source remains uniform, or nearly so, over the distance of a single twist, the induced noise will remain common-mode. The twist rate (also called pitch of the twist, usually defined in twists per metre ) makes up part of

1575-600: The shield. The shield also provides a conduction path by which induced currents can be circulated and returned to the source via a ground reference connection. Such shielding can be applied to individual pairs or to a collection of pairs. Shielding may be foil or braided wire. When shielding is applied to a collection of pairs, it is usually referred to as screening, but usage among vendors and authors in applying such words as screening , shielding , and STP (shielded twisted pair) can be subject to variability. ISO/IEC 11801 :2002 (Annex E) attempts to internationally standardize

1620-436: The shielding is conductive, it may also serve as a path to ground. A foil-shielded, twisted pair cable may have an integrally incorporated grounding wire called a drain wire which makes electrical contact with the shield. The purpose of the drain wire is for easy connection to terminals which are usually designed for connection of round wires. Common shield construction types include: An early example of shielded twisted-pair

1665-450: The specification for a given type of cable. When nearby pairs have equal twist rates, the same conductors of the different pairs may repeatedly lie next to each other, partially undoing the benefits of twisting. For this reason, it is commonly specified that, at least for cables containing small numbers of pairs, the twist rates must differ. In contrast to shielded or foiled twisted pair (typically S/FTP or F/UTP cable shielding ), UTP cable

1710-442: The standards (and thus interoperable with other devices) by accredited third party test labs. All products bearing the KNX logo are programmed through a common interface using the vendor-independent ETS software. Twisted pair Twisted pair cabling is a type of communications cable in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility . Compared to

1755-577: The system. The standardised containers for these datapoints are group objects and interface object properties . The communication system offers a reduced instruction set to read and write datapoint values. Datapoints have to conform to standardised datapoint types , themselves grouped into functional blocks . These functional blocks and datapoint types are related to applications fields, but some of them are of general use (such as date and time). Datapoints may be accessed through unicast or multicast mechanisms. To logically link applications' datapoints across

1800-465: The various shielding designations for twisted pair (TP) cables using an explicit two-part abbreviation in the form of x/xTP , where the first x indicates the shielding for the overall cable and the second x indicates the shielding for individual pairs or quads, where each x can be: Shielded Cat 5e , Cat 6/6A , and Cat 8/8.1 cables typically have F/UTP construction, while shielded Cat 7/7 A and Cat 8.2 cables use S/FTP construction. Because

1845-621: The world are outdoor landlines, owned and maintained by telephone companies, used for voice service. Unshielded twisted pair (UTP) cables are found in many Ethernet networks and telephone systems. For indoor telephone applications, UTP is often grouped into sets of 25 pairs according to a standard 25-pair colour code originally developed by AT&T Corporation . A typical subset of these colours (white/blue, blue/white, white/orange, orange/white) shows up in most UTP cables. The cables are typically made with copper wires measured at 22 or 24 American Wire Gauge (AWG) (0.644 or 0.511 mm²), with

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1890-605: Was IBM STP-A, which is a two-pair 150 ohm S/FTP cable defined in 1985 by the IBM Cabling System specifications, and used with Token Ring or FDDI networks . Before digital communication and Ethernet became widespread there was no international standard for telephone cable. Standards were set at a national level. For instance, in the UK the General Post Office specified CW1293 and CW1308 cables. CW1308

1935-464: Was a similar specification to the earlier CW1293 but with an improved colour code. CW1293 used mostly solid colours on the cores making it difficult to identify the pair it was twisted with without stripping back a large amount of sheath. To solve this problem. CW1308 has narrow rings of the paired colour printed over the base colour. Both cables are a similar standard to category 3 cable. Cables with categories 3 through 7 have 4 twisted pairs. Prior to

1980-443: Was formerly common practice on telecommunication lines. The added inductors are known as load coils and reduce attenuation for voiceband frequencies but increase it on higher frequencies. Load coils reduce distortion in voiceband on very long lines. In this context a line without load coils is referred to as an unloaded line. A bonded twisted pair is a construction variant in which the two wires of each pair are bonded together for

2025-455: Was necessary to protect against existing trams from the outset. Interference on telephone lines is even more disruptive than it is on telegraph lines. Telephone companies converted to balanced circuits , which had the incidental benefit of reducing attenuation , hence increasing range. As electrical power distribution became more commonplace, this measure proved inadequate. Two wires, strung on either side of cross bars on utility poles , shared

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