I am writing the sleeve-loading handover, but one supplier uses ready for request received and the other for access available. I cannot explain the waiting step until they agree what happened.
Drop ready from the discussion draft. Write request received and access conditions established as separate events, then ask both suppliers what each side sets, clears and retains through a timeout or reconnect. Keep ordinary receipt separate from permission to enter the machine area. Only map those events back to signal names once the meanings agree.