klopt, ben effe de link en de .pdf kwijt, maar net email gehad die er redeloijk echt uit zag waarin stond dat cat5e en hoger mogelijk schadelijk zou zijn voor een toestel dat eraan hangt..
zal maandag meer posten.. als iemand dit ook heeft gehoord: posten!
edit: hier het volledige verhaal, geript uit een .pdf
ESTA CPWG Engineering Alert
Cable ESD Alert
There has been a growing trend in the networking industry toward use of CAT-5E and CAT-6 cables and there has also been a noticeable rate of damage being done to Ethernet PHY chips from a phenomenon known as C-ESD (Cable ESD).
Research has shown that the damage comes from a differential voltage that couples through the magnetics after one of the pins on a connector makes contact and current flows from a charged cable through the center-tap of the magnetics. The semiconductor manufacturers are investigating this problem.
IEEE 802.3 will likely make a formal request to the cabling groups, in TIA and the IEC to set a standard limiting this differential voltage. Investigation has found cables that hold a charge all the way up to 6KV, just from ambient charge floating along and sticking to the newer, higher quality dielectrics. This charge builds up on a floating cable which is disconnected at both ends. The cables act like large capacitors and collect charge from the air. Permanent cabling that has one end connected to a hub or switch does not present a danger to devices connected at the outlet. The danger is present only to the first device to be connected to a floating cable.
Recommendations:
1. Do not use CAT-5E or higher cable for portable cable.
2. If CAT-5E or higher is in the permanent cable plant, momentarily short all the connectors on the RJ-45 together to discharge the cable prior to connecting the first piece of equipment to a floating link. Aluminum foil works well.
3. Unless the performance of CAT-5E or higher is required for some other applications using the cable plant, do not use it. It is not required for 10, 100, or 1000BASE-T. Most of the improvement in CAT-5E comes from the connectors, not the cable.
4. 'Cap' unterminated links with an RJ-45 shorting plug for patch panel locations that do not have a jumper to prevent C-ESD build-up.
If you have questions, please contact:
Steven B. Carlson
Co-Chair, ESTA Control Protocols Working Group
Chair, ESTA ACN Task Group
http://www.esta.org
Chair, IEEE 802.3af DTE Power via MDI Task Force
http://www.ieee802.org/3/af/index.html
503.626.4206
FAX 503.626.4206
scarlson@hspdesign.com
zal maandag meer posten.. als iemand dit ook heeft gehoord: posten!
edit: hier het volledige verhaal, geript uit een .pdf
ESTA CPWG Engineering Alert
Cable ESD Alert
There has been a growing trend in the networking industry toward use of CAT-5E and CAT-6 cables and there has also been a noticeable rate of damage being done to Ethernet PHY chips from a phenomenon known as C-ESD (Cable ESD).
Research has shown that the damage comes from a differential voltage that couples through the magnetics after one of the pins on a connector makes contact and current flows from a charged cable through the center-tap of the magnetics. The semiconductor manufacturers are investigating this problem.
IEEE 802.3 will likely make a formal request to the cabling groups, in TIA and the IEC to set a standard limiting this differential voltage. Investigation has found cables that hold a charge all the way up to 6KV, just from ambient charge floating along and sticking to the newer, higher quality dielectrics. This charge builds up on a floating cable which is disconnected at both ends. The cables act like large capacitors and collect charge from the air. Permanent cabling that has one end connected to a hub or switch does not present a danger to devices connected at the outlet. The danger is present only to the first device to be connected to a floating cable.
Recommendations:
1. Do not use CAT-5E or higher cable for portable cable.
2. If CAT-5E or higher is in the permanent cable plant, momentarily short all the connectors on the RJ-45 together to discharge the cable prior to connecting the first piece of equipment to a floating link. Aluminum foil works well.
3. Unless the performance of CAT-5E or higher is required for some other applications using the cable plant, do not use it. It is not required for 10, 100, or 1000BASE-T. Most of the improvement in CAT-5E comes from the connectors, not the cable.
4. 'Cap' unterminated links with an RJ-45 shorting plug for patch panel locations that do not have a jumper to prevent C-ESD build-up.
If you have questions, please contact:
Steven B. Carlson
Co-Chair, ESTA Control Protocols Working Group
Chair, ESTA ACN Task Group
http://www.esta.org
Chair, IEEE 802.3af DTE Power via MDI Task Force
http://www.ieee802.org/3/af/index.html
503.626.4206
FAX 503.626.4206
scarlson@hspdesign.com