Network isolator: Difference between revisions

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{{Short description|Device protecting from electrical spikes}}

{{no footnotes|date=May 2014}}

'''Network isolators''' are installed as part of a copperwired [[Ethernet]] system, as [[galvanic isolation|galvanic isolators]] to reduce the potential for [[electrical injury]] and limit the extent of damage due to [[lightning]] strikes.

NetworkThrough datathe continuesapplied toprinciple of [[electromagnetic induction]], network data beis transmitted across an electrically non-conducting barrier,. throughHigh the applied principle offrequency [[electromagneticAC inductionvoltage]], whereby high frequency AC voltagess conveying [[Data (computing)|data]] are [[transformer|induced]] across an isolating gap.

The network isolator is therefore a [[passive device]], and functions without any requirement of an external power supply. A functional equivalent to network isolators is Ethernet over a small stretch of [[optical fibre]], using media converters or Ethernet switches/network cards with fiber connections on each end.

==Applications==

=== Medical ===

Network isolators are used in the medical industry to protect patients against [[Leakage (electronics)|leakage currents]].

Network connections between [[medical device]]s and [[Ethernet]] networks (and other non-medical devices, such as [[personal computer]]s) must be in accordance with the [[International Electrotechnical Commission|IEC]] standard IEC [[60601-1]] (3rd edition). This standard specifically deals with medical electronic and electrical equipment and systems, and classifies non-medical devices as potential hazard sources. A specific hazard stems from possible differences in ground potentials between network components, which when not properly isolated can result in a leakage current that can flow through the patient, which is dangerous, and potentially [[high voltage#Safety|lethal]]. Such voltage differences can also arise through incorrect installation and wiring of network systems, electrical shorting within damaged cables and cabling, or shorting between damaged network cables and other voltage sources.

Network isolators work to remove this hazard, by electrically disconnecting medical devices from a network. Isolators may be used as network accessories, built into medical devices, or installed within a medical network system. Networks isolators should be installed as close as possible to the medical device in question.

As they serve no therapeutic or diagnostic purpose, network isolators themselves are not classed as medical electronic equipment according to the standard IEC 60601-1, nor do they fall within the scope of the [[Medical Devices Directive]] 93/42/EEC.

They are often installed in the medical field in conjunction with [[isolation transformer]]s, which serve to protect the patient from electrical faults.

===Other applications===

Network isolators have many other applications in overcoming the problems of differing ground potentials across networks, or between network components. For example:

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* For private or commercial networks, where inherent potential differences within a building, or between buildings, become problematic, and a [[Fiber-optic communication|fibre-optic]] solution is not economically viable;

* General usage as filters for shield currents in Ethernet connections.

=== Medical ===

Network isolators are used in the [[medical industrydevice]]s to protect patients against [[Leakage (electronics)|leakage currents]].

Network connections between [[medical device]]s and [[Ethernet]] networks (and other non-medical devices, such as [[personal computer]]s) must be in accordance with the [[International Electrotechnical Commission|IEC]] standard IEC [[60601-1]] (3rd edition)standard. This standard specifically deals with medical electronic and electrical equipment and systems, and classifies non-medical devices as potential hazard sources. A specific hazard stems from possible differences in ground potentials between network components, which, when not properly isolated, can result in a leakage current that can flow through the patient, which is dangerous, and potentially [[high voltage#Safety|lethal]]. Such voltage differences can also arise through incorrect installation and wiring of network systems, electrical shorting within damaged cables and cabling, or shorting between damaged network cables and other voltage sources.

Network isolators work to remove this hazard, by electrically disconnecting medical devices from a network. Isolators may be used as network accessories, built into medical devices, or installed within a medical network system. Networks isolators should be installed as close as possible to the medical device in question. As they serve no therapeutic or diagnostic purpose, network isolators themselves are not classed as medical electronic equipment according to the IEC 60601-1 standard, nor do they fall within the scope of the [[Medical Devices Directive]] 93/42/EEC. They are often installed in the medical field in conjunction with [[isolation transformer]]s, which serve to protect the patient from other electrical faults.

==Technical requirements==

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[[Network cards]] and other [[Computer network#Basic hardware components|active network components]] which are designed to meet IEC 60950 (Safety of Information Technology Equipment), will usually not comply with the more demanding isolation requirements of IEC 60601-1 (Medical Electrical Equipment), and therefore require additional isolation before being used in medical applications.

The transmission quality of a network isolator can be determined by measuring the industry standard parameters or characteristics, for example, [[insertion loss]], [[return loss]], and [[near -end crosstalk]].

By definition, a network isolator completely eliminates each and every direct electrical connection between devices connected through a network connection - specifically all the data lines, and the [[Shielded cable|cable shield]].

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==Models==

Network isolators are commercially available in various designs, to suit customers’ requirements:

* stand-aloneStandalone devices, ready for immediate and simple installation;

* isolatingIsolating components, suitable for [[Original equipment manufacturer|OEM]] manufacturers;

* integratedIntegrated into network wall sockets, for permanent installations.

Voltage ratings (rated in kilovolts) and maximum transmission speeds (e.g. 1000BASE-T) vary between models.

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* [[Ethernet over twisted pair]]

* [[Ethernet physical layer]]

* [[Medical device]]s

==SourcesReferences==

* Krankenhaus IT Journal Ausgabe 05/2008

* DeviceMed Ausgabe 10/2008

==External links==

* EMO Systems [http://www.emosystems.de/en/produkte/netzwerkisolatoren-2/ range of network isolators]

* [http://www.iec.ch/ International Electrotechnical Commission]

* Baaske Medical USA [http://www.baaske-medical.com/index.php?cat=c2_Ethernet-Isolation.html range of medical grade network isolators]

* EMO Systems USA [http://www.emosystems.com range of medical grade network isolators]

[[Category:Networking hardware]]