Ah, Cat-3... When our school district got an old building as a new school, each room had a 25-pair of cat-3 cable terminated just above the door of each room. This made wiring for the building extremely simple, as all we had to do was get the network to the door. The 25-pair carried it all back to MDF. Since then, we have re-wired to Cat-5e. Also, a previous tech had an interesting idea on how he would save cable: Each cable he used was setup the same way: 2 pair were used for Ethernet (Orange and Green), 1 pair for Voice (1 Blue) and the brown pair was used for Appletalk. Only the Appletalk needed a special cable (terminated to an RJ45 to pins 7 and 8). Needless to say, it was both genius and quite the hassle to fix later.
Last, It's amazing how little bandwidth is actually used by the end user. Except for saving some big files, 10Mbit would likely _still_ be enough for the average user. We have been upgrading our network capacity, but we are now focusing on wireless instead of the wired network, as it seems that is where the next big push for bandwidth is. --Matt Ross Ephrata School District Bourque Daniel <[email protected]> , 5/28/2014 9:59 AM: Never used it in prod but it was a fun test PS: 10Base-T was design to work on CAT3 cable at the start!!! Daniel Bourque ----- Message d'origine ----- De : Ben Scott [mailto:[email protected]] Envoyé : Wednesday, May 28, 2014 12:47 PM À : [email protected] <[email protected]> Objet : Re: [NTSysADM] RE: Check cable run length On Fri, May 23, 2014 at 2:40 PM, Bourque Daniel <[email protected]> wrote: > 10 Mbs Full Duplex link can go very far... I test it for fun with a 300 > meters years ago.. No error for a weekend streaming a radio-station... FYI: The 100 meter length limit for Ethernet derives from the time it takes for the jam signal to propagate through the medium after a collision is detected[1]. The jam signal has to be on the bus long enough for all sending nodes to detect it. If the length is too long, a sender might finish sending before the jam signal arrives. That's called a "late collision". The sender can't retransmit in that event, so the frame is lost. But on a full-duplex link, there are no collisions. So what's the next limiting factor? Attenuation? Skew? Crosstalk? Well, the IEEE spec doesn't say. It just says "thou shalt not exceed 100 meters". So you're in uncharted territory. As noted, much longer lengths will often work. I've heard claims of 300+ meters before, and personally seen ~380 feet in production. But you're on your own as far as performance and reliability goes. It may work fine, or demons may fly out of your nose[2]. -- Ben [1] http://en.wikipedia.org/wiki/CSMA/CD [2] http://www.catb.org/jargon/html/N/nasal-demons.html Mise en garde concernant la confidentialité : Le présent message, comprenant tout fichier qui y est joint, est envoyé à l'intention exclusive de son destinataire; il est de nature confidentielle et peut constituer une information protégée par le secret professionnel. Si vous n'êtes pas le destinataire, nous vous avisons que toute impression, copie, distribution ou autre utilisation de ce message est strictement interdite. Si vous avez reçu ce courriel par erreur, veuillez en aviser immédiatement l'expéditeur par retour de courriel et supprimer le courriel. Merci! Confidentiality Warning: This message, including any attachment, is sent only for the use of the intended recipient; it is confidential and may constitute privileged information. If you are not the intended recipient, you are hereby notified that any printing, copying, distribution or other use of this message is strictly prohibited. If you have received this email in error, please notify the sender immediately by return email, and delete it. Thank you!
