Pt. 220, App. B
Appendix B to Part 220—Recommended Pronunciation of Numerals
To distinguish numbers from similar sounding words, the word “figures”should be used preceding such numbers. Numbers should be pronounced as follows:
(The figure ZERO should be written as “0” to distinguish it from the letter “O”. The figure ONE should be underlined to distinguish it from the letter “I”. When railroad rules require that numbers be spelled, these principles do not apply.)
The following examples illustrate the recommended pronunciation of numerals:
||WUN SIX HUNDRED.
||WUN FO-WER ATENINER NINER.
||TOO ZERO DECIMALTHUH-REE.