She rushed to another terminal and checked the computer’s rating of the signal’s recognizability: AAAAA. Before this, no radio signal received by Red Coast ever garnered a recognizability rating above C. An A rating meant the likelihood that the transmission contained intelligent information was greater than 90 percent. A rating of AAAAA was a special, extreme case: It meant the received transmission used the exact same coding language as Red Coast’s own outbound transmission.