[GreenKeys] Here is, answer back, WRU

[John, W9DDD]

Oh, so many ways to do it and I still don't understand the need for an 
end of message device unless you're too lazy to type 4 Ns.

In the mean time here's page of boring research.

Firstly my only in life experience with any answer back was initially 
with the office 28KSR TWX machine and then later I managed to score a 28 
keyboard with it on it.  I used it for call sign DE W9DDD.  I don't 
recall how I got the code bades.  They were less than $5.00 per hundred 
back then, so 20 would have been a buck.  I seem to recall you sent a 
check with your order.  Don't recall how the shipping was calculated in 
advance.  Or maybe there were enough re-usable or UN-coded ones.

(I just recently shredded a bunch of personal checks from the late 
sixties.  There was at least one to Teletype Corporation.  I now wish I 
had saved that one.)

Anyhow, the recent discussion got me off on a search mission.

Quite a while ago I noticed there were two Teletype Specification 
dealing with what seemed to be identical modification kits.  One was 
called an answer back and the other end of message.  (yes, surfing 
navy-radio is more interesting than 95% of television "entertainment")

The recent answer back discussion lead me back to a WU document I had
used earlier to get my 9100C WU cabinet going.  (many parts robbed)

The WU document:
http://www.navy-radio.com/manuals/tty/wu-11753b-intro.pdf

There within that document are several references to various kinds of 
answer back and end of message modifications.

At this point I'll interject an observation I'd had for years but never 
investigated before.  No documentation from AT&T or Teletype I've ever 
seen shows a part number between 200000 and 299999.  Well today I 
specifically looked in a price list (1969 version) for numbers in that 
range.  I found about a dozen.  They all had a WU suffix.

Aha!  That matches the fact that the WU document is sprinkled with 200k 
numbers followed by an IDP number which I assume to be WU's internal 
number for it.  But most references show the normal TT corp number plus 
the IDP.

So the WU document talks about a single character AB (page 7). Drawing 
182426-2 seems to show a solenoid activating one of the keys on a keyboard.

The above linked document also references what appears to be the 
standard TT corp's 21 character device with a specific note that it 
isn't used for Telex service applications (page8).

It mentions various uses of the TT corp LD in conjunction with an 
apparatus that goes in the bottom cavity of the 28.  I can see that 
doing a single character AB with some jumpers (drawing 184635-1 
indicates doing just that) and a multi-character AB with something like 
a stepper switch (not found in drawing package).

-- 
John, W9DDD