Code words shall not contain more than 5 of the characters admissible under rule 18 and shall contain at least one vowel. The vowels are a, e, i, o, u and y the groups ac, aa, ao, oe, ue, and ch in the code words shall be counted as two letters each."The name of the Code used for the wording of a secret language telegram shall be furnished by the sender if required by the office of origin or of destination which will not be charged for.""In Devanagri characters also the code words shall not contain more than 5 characters inclusive of at least one of the following matras, which shall be reckoned as one character for this purpose.
