User Documentation
Installation
2053260000/05/2015
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3.11 Measurement and documentation
Cable measurements form part of the documentation required for many
installations. This involves measuring the properties of the system's cables and
documenting the quality of the network installed.
1 Set the measuring device to the appropriate transmission class.
2 Measure the transmission characteristics (copper) or attenuation
characteristics (bre-optic) of the cable.
3 Record the cable lengths.
4 Print out the values and add to the documentation.
Copper measurement
Use a mobile cable analyser to measure transmission parameters such as:
• connection assignment
• cable length
• near-end crosstalk (NEXT)
• far-end crosstalk (FEXT)
• return loss (attenuation) (RL)
• insertion loss (IL)
Fibre-optic measurement
After assembly, the most important measurement is the space-resolved
attenuation measurement for the installed section using the "Optical Time
Domain Reectometer" measuring device (OTDR). The plug attenuation must be
less than 0.5 dB. It is typically below 0.3 dB and very good attenuation values are
less than 0.1 dB. Two wavelengths (850 nm and 1,300 nm) should be used for
the measurement.
Acceptance then follows.