Comdial 8012S User Manual page 144

In some situations, such as when either you or the distant party is in a
noisy environment, you may have to lift your handset to ensure a
clear conversation. When using your speakerphone, the microphone
and loudspeaker are farther away from you than when you use a
handset. Both the signal from the loudspeaker and the signal to the
microphone must be strengthened.
134 Comdial October, 02