"Ethical communication" simply refers to the practice of conveying honest information in a manner that is not intended to be misleading. In other words, the information should be presented within a context that ensures that the information is not misleading as a result of being conveyed in a sort of vacuum. Information might be true, but if it is not presented in a fair and open manner, then it serves to distort the recipient's understanding.
One form of ethical communication involves the questioning of suspects and witnesses by police officers and prosecutors. Interrogations sometimes involve deliberately misleading information that, while accurate, is conveyed in a manner intended to confuse the suspect or witness. A suspect in a criminal investigation might be told that he or she was seen committing the act in question but not that the supposed witness was known to be unreliable, had viewed the act from a great distance, or had viewed the act under conditions that would obscure visibility. In this case, the suspect, or somebody who looks like him or her, was seen, but this occurred under adverse conditions, rendering any testimony by the witness unreliable.
Another form of ethical communication could involve the techniques used by automobile dealerships to sell vehicles. The buying and selling of automobiles is a notoriously difficult process in which the seller, whether a dealer or a private citizen, is almost always going to conceal certain facts about the vehicle in question regarding its reliability, such as whether it has an oil leak that will require repairs. The prospects of a sell may hinge on a certain amount of deception regarding the vehicle's condition. This would clearly involve unethical communication. A salesman or private citizen selling a car who divulges the entire history of the vehicle, including any accidents in which it has been involved, is practicing ethical communication.
A third example of ethical communication could involve a physician and his or her patient. The code of ethics under which medical professionals operate is very strict with regard to honesty and integrity, but there are bad individuals in every profession, including medicine. Doctors have been known to prescribe medications and recommend procedures that they know are not necessary but will generate revenue. Ethical communication, then, would be those that inform the patient honestly and with no regard for fiduciary matters. Anytime a surgeon informs a patient that surgery is not necessary, it is usually an example of ethical communication in practice.