Basic tdr operation application note 58 velocity factor to operate a tdr it is necessary to tell the tdr the speed of the pulse in the cable.
Tdr cable test open.
Is it at the closet end or user end.
This can be determined by testing a known length of the cable under test and leaving the remote end open.
Plug in the connectorized distribution end of any cat 5 utp cable pulled dark and press the analyzer s test button.
The tdr measures the time between release and return of the low voltage pulse from any reflections.
In the first example the command displays tdr test results for port 1 slot 1 on device 1 in the stack.
Tdr test last run on.
Testing category 5 utp cable.
Tdr time domain reflectometer network analysis cable test first line repair handheld cable test fault finders are designed for first line repair and less specialised field operatives where the requirement is accurate and consistent fault location on the most common types of field problems such as open and short circuits.
Tdr test was never run on gi2 12 examples this.
It can be used to characterize and locate faults in metallic cables for example twisted pair wire or coaxial cable.
In the event of an open or shorted cable the accuracy of length of where the cable is open or shorted is plus or minus 2 meters.
A time domain reflectometer tdr is an electronic instrument used to determine the characteristics of electrical lines by observing reflected waveforms.
This arrangement will leave an open condition on the outlet end of each cable.
Set up the cable analyzer to test cat 5 utp basic link and select the tdr test mode.
Show cable diagnostics tdr int f0 39.
Different types of cable have different velocity factors vf vf is the ratio of the speed of the cable to the speed of light.
This enables the tdr to convert the time the reflected pulses take into distance.
I have this output from a cable diagnostic test that i did.
Sw despacho 01 show cable diagnostics tdr int g1 0 5 tdr test last run on.
Hence for an open end z z 0 and r is a positive reflection.
Sw 01 test cable diagnostics tdr interface g1 0 5 link state may be affected during tdr test tdr test started on interface gi1 0 5 a tdr test can take a few seconds to run on an interface use show cable diagnostics tdr to read the tdr results.
A tdr sends a low voltage pulse into the cable under test and at any impedance change within the cable a reflection will be seen.
Interface speed local pair pair length remote pair pair status.
The pair length can be displayed in meters m centimeters cm or kilometers km.
The time domain reflectometry tdr.
Not only is it possible for the time domain reflectometer to discover where the fault or problem has occurred along the cable it is also possible to discover much about the nature of it as well.
To display the results of the cable analysis enter a command such as the one shown in the following examples at the privileged exec level of the cli.
The results indicate that the port is down or the cable is not connected.
