Kris, 2 pairs are used for 10TX and 100TX Ethernet. One pair is used for transmit, the other one for receive. You need 4 pairs for 1000TX Ethernet. All four pairs are used in both directions. Charles Spurgeon has a nice website about Ethernet including some historical tidbits: http://www.ethermanage.com/ IEEE has the Ethernet standards freely available. http://standards.ieee.org/getieee802/index.html Best regards, Michael Michael Nagel Senior EMC Engineer Motorola GmbH ECC Embedded Communications Computing Lilienthalstrasse 15 85579 Neubiberg/Muenchen - Germany Ph: +49-89-9608-0 Fax: +49-89-9608-2376 e-mail: [email protected] info: http://www.motorola.com/computers
_____ From: [email protected] [mailto:[email protected]] On Behalf Of Carpentier Kristiaan Sent: Mittwoch, 13. Dezember 2006 11:49 To: Emc-Pstc Subject: Ethernet cable: 2 versus 4 pairs. Hello, Does anyone know why an Ethernet cable has 4 pairs where only 2 pairs are used: 1 for TX, 1 for RX. Is it possible to use ethernet cables with just 2 pairs and not have performance or other issues? Best regards, Kris Carpentier Regulatory & Approvals - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
