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.
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.
This arrangement will leave an open condition on the outlet end of each cable.
Interface speed local pair pair length remote pair pair status.
I have this output from a cable diagnostic test that i did.
Testing category 5 utp cable.
How do i pinpoint at which end the pair is open.
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.
If the tdr test has not been run on the port the following message is displayed.
This can be determined by testing a known length of the cable under test and leaving the remote end open.
Tdr test was never run on gi2 12 examples this.
Hence for an open end z z 0 and r is a positive reflection.
Plug in the connectorized distribution end of any cat 5 utp cable pulled dark and press the analyzer s test button.
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.
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.
Sw despacho 01 show cable diagnostics tdr int g1 0 5 tdr test last run on.
The tdr measures the time between release and return of the low voltage pulse from any reflections.
This enables the tdr to convert the time the reflected pulses take into distance.
Different types of cable have different velocity factors vf vf is the ratio of the speed of the cable to the speed of light.
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.
Is it at the closet end or user end.
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.
It can also be used to locate discontinuities in a connector printed circuit board or any other electrical path.
Show cable diagnostics tdr int f0 39.
The results indicate that the port is down or the cable is not connected.
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.
A time domain reflectometer tdr is an electronic instrument used to determine the characteristics of electrical lines by observing reflected waveforms.
The pair length can be displayed in meters m centimeters cm or kilometers km.
