NVP speed signal propagation over twisted pair relative to the speed of light

Cable F / UTP 300/24 ​​4P FutureCom, Cat.5e, LSZH / FRNC, blue, 305 m, Corning

NVP 74%

OC-FTP5E (200) FTP cable 4 × 2 × 0,51, cat. 5e-SL, KPVE-AM (200), 305 m, Odeskabel

68% NVP

PFL5504DG-KG TX5500 ™ Shielded Twisted Pair (FTP), category 5e, 4 pairs, solid (solid), the screen — a foil, LSZH Panduit

67% NVP

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NVP

Nominal Velocity of Propagation — nominal velocity of propagation in the medium of transmission. In the SCS under this parameter is the speed of propagation of electromagnetic waves in a twisted copper pair. NVP is expressed in percentage of the speed of light in vacuo. For category 3 twisted pair, 5e and 6, as a rule, NVP is in the range from 68% to 72% for highest performance and improved cable (e.g., Category 7 or 7A) — 80%.

NVP is used in the measuring equipment (field tester for twisted pair) to determine the electrical length of the cable. The accuracy of his job will depend on the accuracy of the measurement of length, and the displayed distance to the fault (if the tester diagnostic functions). Cable manufacturers indicate the value of NVP for each cable type in catalogs and specifications for products.