At 03:55 AM 7/18/2003 +0000, "Chuck Whose Road is Ever Shorter" wrote: >""Zsombor Papp"" wrote in message >news:[EMAIL PROTECTED] > > At 01:20 AM 7/18/2003 +0000, Bill wrote: > > >Just learning basics of fiber communication. > > > > Btw, optical communication is indeed an interesting topic. Does anyone >have > > a recommendation for a good book on this? I would be very interested in a > > book (let alone web site) that explains the fundamental principles > > (modulation, dispersion, spectral width, etc) in a great detail, but > > without making my brain explode with thousands of formulas. (Yeah, I know, > > it's not an easy request.) > > > > For example, why exactly do we need that conditioning cable when >connecting > > a MM cable to a SM interface? > > >not that CCO necessarily provides intimate technical details, but if you >read the footnotes you can infer that it has to do with laser strength and >signal saturation.
That's probably just one part of the problem. That same footnote goes on to say that "mode-conditioning patch cord is required for link distances *greater* than 984 feet". Surely the signal doesn't get stronger as the distance increases? See also this page: http://www.l-com.com/content/ResourceCenter/Tips/pages/fiber_06.htm which talks about Differential Mode Delay (DMD) and hints about the importance of positioning the SM core against the MM core. This DMD sounds like modal dispersion, but if it really is modal dispersion, then why is the SM interface affected more by this than the MM interface? Btw, as for the laser strength and saturation, I am also wondering why that doesn't present a problem with SM cables. Because the small core doesn't carry as much energy as the large core of the MM cable? Or maybe it is a problem even for SM, they just assume that you wouldn't use SM cable for a distance measured in "10s of meters"? Thanks, Zsombor >http://www.cisco.com/en/US/products/hw/modules/ps872/products_data_sheet09186a008014cb5e.html >watch the wrap. > >probably the same reason why the minimum length of a fiber patch ( >multimode ) is 3 meters / 10 foot > > > > > > Thanks, > > > > Zsombor > > > > > I am not sure about which fiber > > >cable I saw but it was orange and basically connected two 3550's >together. > > > > > >The fiber had two connectors on each side. One was blue and the other was > > >red. > > > > > >How is it normally connected? I guess the switch ports are receive and > > >transmit. So, does that mean if you connect red on the left port on one > > >switch, you would connect the red on the other side of the cable to the > > >right port of the switch? > > > > > >Thx > > >bill Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=72559&t=72544 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
