In documentation for most any console, receive audio is described as having a 30 decibel (db) knee of compression: for a 30 db variation in input audio level, the speaker volume changes by 3 db. This is desirable because persons calling on the radio who are whispering or yelling would ideally be intelligible and be presented to the console user at roughly the same volume. It helps reduce the need to constantly adjust the volume control to accommodate different voices. It also helps the console user talk on the telephone without loud sounds coming from the remote control speaker. A professional dispatcher will often set the console volume at a setting similar to the telephone's perceived volume. This allows the dispatcher to shift her attention between the radio and the phone without continually adjusting volume controls during a conversation.