I'm looking for historical records showing that parties using coded messages (from the Egyptians to the Romans to actors in the American Civil War, etc) would sometimes stipulate deadlines by which a response must be received. The encoding of messages needs to be by hand (so no computers/machines involved).
I know there is a project to decode thousands of Civil War telegrams, but I have been unable to find a collection of the decoded messages to read. And no history books I've encountered that describe ancient military protocols include a description of deadlines for replies.
The famous Zimmerman Telegram (captured and decoded by the British in WW I) makes an offer to Mexico, but does not appear to have an expiration date attached to it.
Surely if a message is sent to (say) a general in the field and no response is received by some preordained deadline, an action is taken, right? No one will just wait forever?
I would appreciate any examples you know of, or suggestions on where I might look to find examples. I have already reviewed David Kahn's book "The Codebreakers."
Amended to Add: It's fine if the time limit was not explicitly stated in each message as long as it was well-established somehow. For example, if say a Roman War Manual stated that "if no response is received within 3 days, we assume the courier was lost and send another message." That would be enough for my purposes. But I'm unable to find records of such policies in historical records (for military, diplomatic or other secure-messaging settings).