Some Ethernet history will explain the situation: 10BaseT Ethernet was designed to run on the same cable with telephone to simplify connectivity to cubicles. Non-telco pins were selected for Ethernet so RJ-45 jacks could accept either a telephone- or Ethernet plug. This combination wiring scheme was never very popular in the USA, and totally illegal in Europe (where telco wiring MUST be separated from all other wiring). All references to a combined Ethernet-telco wiring scheme were removed from NIC Installation Instructions around 1991 because European customers were being advised to violate the law!! The RJ-45 jack specified in for T-P in ANSI/IEEE 802.3 is an artifact of a 'connectivity improvement' that never made it. Also 1) TIA/EIA-968 replaced CFR 47 Part 68 now that ACTA is in charge 2) TIA/EIA-968 has no reference whatsoever to Ethernet 3) It is very difficult to change ANSI/IEEE802.3 retroactively David
-----Original Message----- From: John Shinn [mailto:john.sh...@sanmina-sci.com] Sent: Wednesday, January 02, 2002 11:56 AM To: david_ster...@ademco.com; john.sh...@sanmina-sci.com; ows...@cisco.com; rhe...@vicon-cctv.com; emc-p...@majordomo.ieee.org Subject: RE: RJ45 filtered connector David: The pertinent and defining specification is contained in the FCC Rules, 47 FR Part 68. Everything else is a misuse of the original intent. An RJ11 is also defined there. ALL "RJ" designations are specified for use within the telephone industry. Is is too bad that the Networking groups chose to use the same designation for the same modular plug with different wiring. That is the same as calling all DB-25 connectors an RS-232 connector, even if used for a different application. John -----Original Message----- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of david_ster...@ademco.com Sent: Wednesday, December 26, 2001 9:12 AM To: john.sh...@sanmina-sci.com; ows...@cisco.com; rhe...@vicon-cctv.com; emc-p...@majordomo.ieee.org Subject: RE: RJ45 filtered connector John, The pertinent specification, ANSI/IEEE 802.3 (a.k.a. ISO/IEC8802.3), describes the Ethernet physical layer plug/jack as an "RJ-45". ArcNet twisted pair was "RJ-11". If you purchase jacks that include internal filters, be sure the filters are designed for Ethernet/F-E (10BaseT & 100BaseTX). Some ferrite filters are designed to suppress digital noise in voice telephone lines. These ferrites can cause 'back pressure' on the digital signal, resulting in cable-length sensitivity; i.e. the impedance curve no longer meets 802.3. You can live with cable-length sensitivity on emissions (to 'isolate' the EUT), but expect diminished RF immunity with certain cable lengths when filters are inserted in the T-P line. Ethernet components are rigorously tested for 802.3 compliance (waveforms, jitter, SQE, bit-error rate) and for compatibility with components from other manufacturers. These compatibility-suite tests are performed without any additional T-P line filters. Any altered interface is your responsibility; results may or may not represent real world installations. David -----Original Message----- From: John Shinn [mailto:john.sh...@sanmina-sci.com] Sent: Thursday, December 20, 2001 6:10 PM To: 'Bill Owsley'; 'John Shinn'; 'Reginald Henry'; emc-p...@majordomo.ieee.org Subject: RE: RJ45 filtered connector Acutally, the term "RJ" is used by the FCC for designating connectors that are part of the registration (now approval) process. So why would you want to call a ethernet connector by a designation used by the telephone industry? I am not going to police the use of the term, but I wanted to put that information out to everyone. Regards, John Shinn -----Original Message----- From: Bill Owsley [mailto:ows...@cisco.com] Sent: Thursday, December 20, 2001 2:32 PM To: John Shinn; 'Reginald Henry'; emc-p...@majordomo.ieee.org Subject: RE: RJ45 filtered connector so if we called it an RJ-48C, would that be better ?? At 04:56 PM 12/20/2001 , John Shinn wrote: Although it may suprise some, and I may get flak, but an RJ45 connector is an specific configuration used exclusively for a programmable data connection. It has a specific wiring configuration. The "RJ" stands for Registered Jack. This is an FCC designation of that specific configuration. There is nothing against using an 8-pin modular plug/jack for 10Base-Tor 100Base-T, or even microphone inputs to my Ham radio, but do not call it a RJ45. Now, yes, there are several vendors that produce shielded and filtered 8-pin modular jacks. I remember using them and working with several vendors a few years ago, but I would suggest you look at the website or catalogs of the major connector suppliers. John Shinn, P.E. Manager, Lab. Operations. Sanmina-SCI -----Original Message----- From: owner-emc-p...@majordomo.ieee.org [ mailto:owner-emc-p...@majordomo.ieee.org]On <mailto:owner-emc-p...@majordomo.ieee.org%5DOn> Behalf Of Reginald Henry Sent: Thursday, December 20, 2001 10:51 AM To: emc-p...@majordomo.ieee.org Subject: RE:RJ45 filtered connector To All, Can anyone out there tell me where I would be able to purchase a fully shielded and filter RJ45 connector that is Bulkhead mountable. The RJ45 must be able to handle data rates from 10Base T to 100Base T I will be performing CE testing in the chamber so it must be bulkhead mountable ! Thanks and Happy Holidays to YOU ALL ! Reg ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ <http://www.ewh.ieee.org/soc/emcs/pstc/> To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ <http://www.ewh.ieee.org/soc/emcs/pstc/> To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. Bill Owsley, ows...@cisco.com 919) 392-8341 Compliance Engineer Cisco Systems 7025 Kit Creek Road POB 14987 RTP. NC. 27709
