Mailing List Archive


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Shielding of CAT 6 cables (was Re: [tlug] FTTH ISP recommendation)



jep200404 wrote:
Edward Middleton wrote:
My point was that standard phone cables unlike category 6 cable wasn't designed for high bandwidth applications and so is not going to have adequate shielding.

What's the relationship between bandwidth and shielding?

Shielding causes decreased noise or increased Signal to Noise Ratio SNR. For the relationship between SNR, bandwidth and channel capacity, from wikipedia[1]


   C = B log_2(1 +(S/N))

   C is the channel capacity in bits per second;
   B is the bandwidth of the channel in hertz;
   S is the total signal power over the bandwidth, measured in watt or
   volt2;
   N is the total noise power over the bandwidth, measured in watt or
   volt2; and


If you have a lower bandwidth cable B, like a phone cable, you need a higher signal to noise ratio S/N to gain the same channel capacity.


How much shielding does the CAT 6 standard require a CAT 6 cable to have?

Good point, Category 6 UTP obviously has none, but it has greater bandwidth so can sustain higher channel capacity under lower SNR.


Edward

1. http://en.wikipedia.org/wiki/Shannon-Hartley_theorem


Home | Main Index | Thread Index

Home Page Mailing List Linux and Japan TLUG Members Links