08 What is CCIR 476?

https://en.wikipedia.org/wiki/CCIR_476

CCIR 476 is a character encoding used in radio data protocols such as SITOR, AMTOR and Navtex. It is a rewrite of the ITA2 character encoding, expanded from a five-bit code to a seven-bit code.

In each character, exactly four of the seven bits are marker bits and the other three are space bits. This enables the detection of one-bit errors.