Simulate cat5 or cat6 cable with LTSpice


Joined Mar 14, 2008
Do you want to simulate it as a high-frequency transmission line, or just a cable with inductance and capacitance for low frequency signals?


Joined May 20, 2015
Above the symbol of the twisted pair are specified specific parameters (parameters for one meter) - specific resistance of one core - r, specific capacitance between the conductors of the pair - C, specific capacitance between the shield and one conductor - Cws, specific resistance of the screen - Rs. The last value is not given and I took Rs=r/10.
The length of the twisted pair is Len.
When I made the model I didn't know that there are cat5 and cat6 and I took the parameters of some random twisted pair. Now I don't remember which one. It wasn't important to me at the time.
I used the Twisted_pair1024 element. The model consists of 1024 cells.


Thread Starter


Joined Apr 14, 2021
Thanks Bordodynov, do you have any links where to find the characteristics of the cat5 cable? I've been looking for 3 hours but I can't find a paper that lists in an exhaustive way the parameters you reported. it's very frustrating


Joined May 20, 2015
It all depends on the length of the twisted pair.
Maybe 32 sections are enough for you. It all depends on the edge of the signal you're transmitting. N=Len is fine.
Why are you giving a sinusoidal signal?