UTP Cat 5 2

[maxamillian]

Question play in my mind as the books always said that suggested usage on UTP Cat 5 cables to be used no more than 100metre.
Yes.I understood that the signal will be weaker as the length increase.But why? Was it a physical limitation? or the twisted pair that cause the limitations?
Where can I find the details of the "unknown"

 

[melone]

Impedance is a function of length. L gets bigger, R, L and C get bigger.

 

[robertjo24]

The "twist" in the twisted pair serves to reduce cross talk between pairs, (known as NEXT, FEXT, EPFEXT, etc.). The specification for the termination of CAT5 cable is that the untwisted horizontal section of cable should be no more than 1/2", meaning, do not untwist the cable more than 1/2" to make a termination. This is why we use 110-type punch down blocks for CAT5 and higher terminations, where as CAT3 and lower can be terminated on a 66-type down block, (telephone, T1, etc.). When installing RJ-45 connectors on CAT5 cable, only untwist what is neccessary to make the connection.

If you exceede the 1/2" rule a little, yes the cable will most likely work. If you exceede the 100 meter rule a little, yes the network connection will most likely work. If you run a network analyzer on a properly terminated cable, and one that fudged the rules a little, I would imagine you would see the differnces in the test results, and it would be an area that could cause problems in the future.
As a rule, I adhere to the cabling rules/guidelines to ensure quality installations and full bandwidth availability.

 

[BTHBV]

it is 90 meter to be exactly

 

[IRstuff]

The physical limitation is the shear amount of capacitive and inductive load which reduces the maximum frequency of operation.

Since the signal is so weak, it is essential to have adequate performance from the twisted-pair cable as that's what provides the common-mode noise rejection.

TTFN

 

[Heydave]

Signal loss in its simplest form is not the distance issue but how the signal decays. The higher frequency components are attenuated faster than the lower frequencies. When you look at the pulses in the signal, they come in different widths which translate to different amounts of energy at different frequencies. Wider pulses are not attenuated as much as narrow pulses. At some point, the wide pulses completely dominate and the data content is lost. Modulation schemes that restrict data streams to a single pulse width or frequency carrier perform much better but are more difficult to implement. T1 is an example of a fixed pulse width but does not work well in packet network because of the lengthy sync time. Frequency based schemes such as DMT ADSL also have a lengthy setup time but both schemes carry data a lot farther than 10/100T.