The sender will have some kind of meaning she wishes to convey to the receiver. It might not be conscious knowledge - it might be a sub-conscious wish for communication. What is desired to be communicated is an idea, perception, feeling, or data. It is a part of her reality that she wishes to send to somebody else. Something will be transmitted across a distance in the shared space. This can be thought of as an object, particle, wave, or flow. It might be sound vibrations, rays of light, words, pieces of paper, cannon balls, body language or telepathy.