X-Received: by 10.50.114.105 with SMTP id jf9mr5137286igb.1.1394355389561; Sun, 09 Mar 2014 00:56:29 -0800 (PST) Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!ur14no4417426igb.0!news-out.google.com!bw18ni7155qab.1!nntp.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.posted.gcicommunications!news.posted.gcicommunications.POSTED!not-for-mail NNTP-Posting-Date: Sun, 09 Mar 2014 03:56:28 -0500 Newsgroups: alt.os.linux,alt.os.linux.ubuntu,comp.os.linux.networking Subject: Re: How to set up a spare Linksys WRT54Gv2 as a wired access point network extender References: <79349$531ada84$43da7656$10059@nntpswitch.blueworldhosting.com> <531B1133.3030405@djph.net> <46871$531b684c$43da7656$13519@nntpswitch.blueworldhosting.com> <1nsnh9t7sjbov63ns8iceejos9b4mvc7jj@4ax.com> From: floyd@apaflo.com (Floyd L. Davidson) Organization: __________ Date: Sat, 08 Mar 2014 23:56:19 -0900 Message-ID: <87mwgzoimk.fld@apaflo.com> User-Agent: gnus 5.10.6/XEmacs 21.4.15/Linux 2.6.19 Cancel-Lock: sha1:uyiYS9ZlvkfWNjT/7O8/qEZ2cw0= MIME-Version: 1.0 Lines: 55 X-Usenet-Provider: http://www.giganews.com NNTP-Posting-Host: 24.237.124.187 X-Trace: sv3-nDMmUP5q2j9sU0qAg5A60v0xBbfCgwLa3umL/o+54Wizph0gZA1K2NbhLUECd0KhSfOMyt40QPWTwwy!XyAN0BT+7SyaAXSO4NyPuHmSTGnGRruszsZSehFsPfW86UaA+/BqQxmHKHl4ROvz+ZNAqF0X X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 3987 Content-Type: text/plain; charset=us-ascii Xref: csiph.com comp.os.linux.networking:2803 DecadentLinuxUserNumeroUno wrote: >On Sun, 9 Mar 2014 02:49:00 +0000 (UTC), Bit Twister > Gave us: > >>On Sat, 8 Mar 2014 10:58:10 -0800, Liam O'Connor wrote: >>> >>> Oh? I am very confused by these wiring "standards". >>> >>> I realize that what *really* matters most is that whatever >>> color is used on one end, is used on the other end (since >>> a wire is a wire, no matter what color it is insulated). >> >>Up to a point. You do not want to split the wire pair. That can cause >>60 hz hum and/or cross talk. Pairs are twisted to reduce external emi. >> >>For anyone interested what the color pairs are for different plugs: >>http://en.wikipedia.org/wiki/Registered_jack#Powered_version_of_RJ11 > > NOT "up to a point". The actual wire pair used on each numbered pair >DOES matter. The original concept was Pair 1 on pins 4/5, Pair 2 on pins 3/6, Pair 3 on pins 2/7 and Pair 4 on pins 1/8. That works fine, just as stated, "up to a point"! For voice frequency or low speed data... but the distance between pins on the plug for Pairs 3 and 4 is too great for high speed data. At high bit rates the intention is to keep the Tip and Ring of each pair closer together than worst case. Hence pins 1/2 are a pair and pins 7/8 are a pair to maintain physical proximity on the plug. The significance is the length of conductor that is not twisted with it's mate. Higher frequency data requires a higher twist rate, but the physical construction of the plug means there is about 9/16" more with no twist. If the conductors are parallel to each other spaced only by the insulation that short distance matters less than if they are further separated. When they are 3/8" apart the effect is of two independant wires in space, rather than a parallel transmission line or twisted pair transmission line. The T568A/B standards use the pairs on pins 1/2 and 3/6. Up to a point that is close enough proximity, but it isn't the best that could be done with that physical socket/plug either. All that said, for the use described by the OP, it makes no difference in practice! I doubt that even Gigabit EtherNet would blink at different pin spacing of pairs in a typical environment. When the connection is to a 6 foot rack with nothing but jack fields and cables, it counts. Not in a home environment with only minor potential for crosstalk. -- Floyd L. Davidson http://www.apaflo.com/ Ukpeagvik (Barrow, Alaska) floyd@apaflo.com