These procedures have been developed, tested under the most difficult of conditions, then revised to implement the lessons learned, many times since the early 1900s. According to ACP 125(G) and the Virginia Defense Force Signal Operating Instructions:Voice procedure is designed to provide the fastest and most accurate method of speech transmission. All messages should be pre-planned, brief and straightforward. Ideally, messages should be written down: even brief notes reduce the risk of error. Messages should be constructed clearly and logically in order not to confuse the recipient.Voice procedure is necessary because: