Neper (Np) is a logarithmic unit for indicating ratios.
Unlike decibels, the neper is based 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, the neper and the decibel. In telephone technology, the unit neper is still used.