To use the phone in public places, we should take into consideration participation is primarily. We should use audio in a conversation in a normal voice level should not shout or vulgar parlance.
Using the phone in public, we should take into account mainly involved. We should use sound in a conversation at normal sound levels should not shout or rude.
Using the phone in public concern should be involved as the core. We should use the voice in the conversation in the volume that normally should not shout or rude.