In the ATO message format, what does a hyphen signify?

• A. End of the Field
• B. Not Applicable
• C. No Data in the corresponding field.
• D. Data Valid

Answer: (C)

In the ATO message format, a hyphen is used as a sentinel value to indicate that no data exists for that field. It acts as a clear signal to both humans reading the message and automated parsers that the data for that field is intentionally missing, not provided, and should be treated as “No Data in the corresponding field.” This helps preserve the structure of fixed-width or delimited fields and prevents misinterpreting an empty space or a zero as actual data.

This is why the hyphen corresponds to No Data in the corresponding field. It’s not simply indicating End of Field or Not Applicable, and it certainly doesn’t mean the data is valid. If a field were Not Applicable, a different convention would typically be used, and a value of Data Valid would contradict the presence of a hyphen.