Should the nuclear alert messages have included a parity check?
“About seven months [after the training tapes false alarm], U.S. warning systems generated three more false alerts. … A computer at NORAD made what amounted to “typographical errors” in the routine messages it sent to SAC … about missile launches. While the message usually said “000” ICBMs or SLBMs had been launched, some of the zeroes were erroneously filled in with a 2, e.g. 002 or 200, so the message indicated that 2, then 200 SLBMs were on their way. Once the message arrived at SAC, the command took survivability measures by ordering bomber pilots and crews to their stations at alert bombers and tankers and to start the engines.”
"According to the Pentagon, what caused the malfunctions in June 1980 was a failed 46¢ micro-electronic integrated circuit (“chip”) and “faulty message design.” "
http://nsarchive.gwu.edu/nukevault/ebb371/