Number Telling Methods for Two-, Three-, and Four-Digit Numbers
Sol Adler · The Journal of the Acoustical Society of America · 1955
Number-telling accounts for 25% of the words used in transmission during air operations. Thus, optimum transmission methods are a necessity. Various types of repetition methods are compared for relative performance values. Two-digit numbers were tested as separate signals (i.e., “three-five”) and as a group presentation (i.e., “thirty-five”) with the former attaining significantly superior reception. Voluntary stuttering of the two digits were found to further increase their intelligibility. Three-digit numbers were tested to determine the best method of signal presentation; again the individual digits were superior. Tests indicated that straight repetition of the signal was inferior to an alternative form (i.e., “one-hundred twenty-three, I say again, one-two-three”). A counting method of three-digit transmission whereby redundancy is introduced by counting up to any digit from the two previous proved far superior to any of the best repetition methods (i.e., “six, I count: 4, 5, 6; eight, I count: 6, 7, 8”). Four methods of presentation of the four-digit numbers were compared, with the individual digit-telling style again yielding a superior intelligibility score. The above work was carried out under contract with Operational Applications Laboratory, Washington, D. C.