Neper (Np) is a logarithmic unit for indicating ratios.
, neper isbased on the natural logarithm with base "e", corresponding to 2.7128. All level, gain and attenuation values can be expressed in decibels (dB) or the previously used neper, where one neper is 8.686 dB.
The International Telecommunication Union (ITU) recognizes both units, neper and decibel. In telephone technology, the unit neper is still used.