Level refers to the relative strength of the signal and is measured in decibels. LINE level sources are much-amplified signals over MIC (microphone) level signals. Line level is usually between -10 to +4 dbm in strength while MIC levels are normally -60 dbm. The line output standard designed to drive a load of 600 ohms or greater, at a mean signal level of 0. 775V RMS.
An exception exists in respect of compact disc players, where the output level is most commonly 2V RMS.