They could infer the complete message even when it was not explicitly stated in the text.
Each complete message takes 750 seconds (12 1/2 minutes) to complete.
Usually there is a series of such interchanges until the complete message is sent.
The pieces, called keys, are designed so that even a small number of them can be assembled into a complete message.
We have the other three parrots now and can unravel the complete message at my leisure.
It's hard enough to break a code when you have the complete message.
When at last he had done he read the complete message.
"Even in the middle of this war, they have taken time to write us such complete messages."
What you have heard is apparently a complete message.
"Getting a clear, complete message and deciding what it means took this long."