What information is contained in the preamble of a formal traffic message?

In the National Traffic System (NTS), a formal radiogram is divided into specific parts: preamble, address, text, and signature. The preamble comes first and serves as the administrative header for the message. The preamble contains essential routing and tracking information, such as the message number, precedence, handling instructions, station of origin, check (word count), and date/time. The email address, recipient address, and telephone number belong in the address block of the radiogram, not the preamble. Therefore, the preamble is strictly for the metadata needed to track and route the message accurately.