face to face
This channel is a channel that can best be seen in the behavior of a person and can respond instantly makes the work fast and more efficiently.
telephone
This communication can be heard and can reply immediately, but can not see the facial expression of the opponent, so The caller must be communicated to the opposing understand the purpose to avoid errors in their work.
E-mail
The electronic letter .You need to check to know that who sent an email to you. Currently, the most widely used
letter
Write a letter to find a opponent, which require a period to send that made the operating in organization delayed.
formal report
is a Writing formal reports and no response