The Vietnamese phrase "đánh dây thép" literally translates to "hit the wire" and is an idiomatic expression that refers to sending a message, especially a telegram or a communication over a long distance. It is considered an old-fashioned way of communicating, similar to the phrase "sending a telegram" in English.
In modern contexts, the phrase might be used metaphorically to mean reaching out to someone or communicating important information, even if the communication method has evolved (e.g., using email or instant messaging).
While the primary meaning relates to communication, in some contexts, it can imply urgency or the importance of getting a message across quickly.
"Đánh dây thép" is a culturally rich expression that captures the essence of communication before the digital age.