Electrons travel at approx. constant speed (  20 cm or 8” per ns, 1 ns = s NVP * speed of light) Propagation delay (max 555 ns later..) Traveling signals is like electrons following a somewhat rocky path

Atenuación (Perdida de inserción) Menos electrones! Calor! Existen baches en el camino….

Crosstalk!! A level problem in the electronic road will cause some electrons to fall on an adjacent road On top of that: the road is not level and electrons fly off!

Near End Crosstalk is by the electrons that return back to the beginning Near End Crosstalk (NEXT)

Far End Crosstalk is by the electrons that continue to the far end Far end crosstalk ( FEXT )

At a receiver input you need more signal electrons than stray electrons Combine two effects: attenuation and NEXT: S/N = ACR Look here!

Alien Crosstalk Alien crosstalk occurs between cables