In case you missed it, I have updated backslash to include the info you found. All we really need now is some record that says what was it used for. --John Maynard Friedman (talk) 11:43, 8 January 2021 (UTC)[reply]

I have come into contact with another person with the same machine who is now also looking for the same information.Tadfafty (talk) 16:58, 8 January 2021 (UTC)[reply]

And again[edit]

In case you miss it, FYI I have updated the article again after I found a paper that cited a 1937 TTY manual – stored on the same US Navy archive. --John Maynard Friedman (talk) 12:00, 15 March 2021 (UTC)[reply]

And another[edit]

Now at least 1934, probably 1919, thanks the GPO. --John Maynard Friedman (talk) 21:11, 15 March 2021 (UTC)[reply]

The 1934 I have seen before, I thought that was the one I initially sent you. Though I didn't hear anything about 1919.Tadfafty (talk) 01:34, 16 March 2021 (UTC)[reply]

I must have had a sudden rush of blood to the head. The keyboard shown in the GPO technical pamphlet (fig 12, page 15) does not have a backslash. (The paphlet was first published in 1919, the copy shown is a 1934 reprint.) (The one you sent me was the Teletype Corp one.)

By the way, I did some research on US copyright law. Until 1976 (or thereabouts, will dig it out again if it matters), a document was protected by copyright for 28 years after first publication, though it could be renewed for another 28. IMO it is a reasonable assumption that Teletype would not have bothered to renew the copyright on documentation for a device that had been obsolete for many years. --John Maynard Friedman (talk) 12:01, 22 March 2021 (UTC)[reply]

I would say that when the machine became a Teletype in the 30s seems to be when the \ came in. Though the 20s seems to not have much info for this machine.Tadfafty (talk) 03:52, 17 May 2021 (UTC)[reply]

They were used in Army & Navy command & control including Worldwide Military Command and Control System, timesharing systems, early UNIX. So maybe declassified US military specialization training manuals, ARPANET documents? .... 0mtwb9gd5wx (talk) 11:09, 17 August 2021 (UTC)[reply]

This is the wrong kind of teletype for UNIX and such, not ASCII or Boudot but Wheatstone. Tadfafty (talk) 18:30, 17 August 2021 (UTC)[reply]