When was the first documented use of "do you copy" by the military?

I have found a documented use from 1960. But WWII movies use the expression. So are the movie people making it up, or do they know something I don't?

Solution 1:

Finding anything for this meaning of copy prior to @Pete 's 1955 example in a comment above is proving difficult. Lists of prowords or procedure words I've come across from the 1950's do not contain copy and Wikipedia articles mentioning this meaning of copy do not document when it began to be used. I would point out that the OED's earliest citation for Wilco (Will comply) is from 1946 (and I've found an example from 1943 in Google Books).

However, the OED does have a 1930 example of copy with this meaning under read (v.):

13.a. intransitive. To receive and understand a message by radio (occasionally, by telephone).

In most cases, formed by omission of me from Do you read me?

1930 Amer. Speech 5 289 The receiving operator ‘receives’, ‘copies’ or ‘reads’.

Lexico has this sense for copy:

copy (v.)

No object Hear or understand someone speaking on a radio transmitter.

this is Edwards, do you copy, over

as does m-w:

In radio/military communications: to acknowledge receipt of (a message)

The operator of the Titanic was busy figuring his accounts and did not bother to copy the message. A little later in the afternoon, another ship named the Baltic called the Titanic to tell her about icebergs that were in her way. — Rev. Robert P. Lawrence

However, I don't see it in the OED under the verb copy.