[Milsurplus] red/black TTY shipboard question

[Nick England]

I apologize for not being very clear - Yes, I am familiar with
red/black, TEMPEST, etc. - first learned about them 40 years ago when
I was an engineer for the Naval Electronics Systems Command.

My question now is how and why this switch/indicator set-up was used -
Why was TTY gear in a classified space sometimes switched to a black
(unclassified) circuit - to copy or send what kind of traffic? What
gear was typically plugged into this switch box? And am I correct in
my guess as to why it says CAUTION on the UNCLASSIFIED indicator?

thanks,
Nick

--------------------------

And just to (I hope) straighten things out - RED signals are NOT
ENCRYPTED - this is the classified plain text *before* it is encrypted
or after it has been decrypted.
"OPEN FIRE AT 0500" is RED UNENCRYPTED text

After it is encrypted the signal is BLACK - meaning it is unclassified
and can get transmitted into the aether where every Ahmed, Boris, and
Kim in the world can copy it but they can't figure out what it
actually means.
"DRTGH SHPUH QTJFV" is BLACK ENCRYPTED text

BLACK signals are:
1) unclassified stuff that isn't worth hiding (unencrypted requests
for more coffee mugs); or
2) classified stuff that is worth hiding (encrypted requests for more
nukes); or
3) unclassified coffee mug requests that are EFTO (encrypted for
transmission only).

Confusing people might be a message header that says SECRET followed
by a whole bunch of seemingly random letters (encrypted text). This
means that when it is decrypted, the contents of the message are
classified SECRET. But the encrypted version is unclassified - you
really can't keep a secret while feeding it into a 40KW transmitter!!!

cheers,
Nick

On Mon, May 7, 2012 at 3:33 PM, Nick England <navy.radio at gmail.com> wrote:
> Howdy gang - I'd like to understand how a couple of items were
> actually used aboard Navy ships -
>
> One is a key-operated CLASSIFIED/UNCLASSIFIED teletype line switch SA-734/SG
> http://www.navy-radio.com/rtty/misc/sa734-sg-91.jpg
> I presume CLASSIFIED means red (unencypted) circuits and UNCLASSIFIED
> means black (encrypted)?
> So an UNCLASSIFIED switchboard would be an SB-1203
> http://www.navy-radio.com/rtty/patch/sb1203-02.jpg
> and a CLASSIFIED one would be an SB-1210
> http://www.navy-radio.com/rtty/patch/sb1210-02.jpg
>
> OK - the actual teletype equipment connects to this switch via two
> 1/4" phone jacks, only one of which is uncovered at a time by turning
> the key. What TTY equipment would be plugged in here - a 28KSR on a
> roll-around stand? or test gear? or something permanently mounted but
> with a flexible line cord? In other words if I saw one of these
> switches shipboard, just what would be plugged into it?
>
> And the related device is the UNCLASS/CLASS warning lamp ID-866/SG
> http://www.navy-radio.com/rtty/misc/id866-sg-01.JPG
> I assume this was controlled by the switch and installed near the
> teletype equipment.
>
> So the red WARNING lamp lets you know that this is a circuit for
> UNCLASSIFIED info only and you'd better not type anything on that KSR
> unless you want Boris and Natasha to read it.
>
> I convinced myself all this made sense until I looked at this
> installation aboard USS New Jersey, which seems exactly opposite....
> http://www.navy-radio.com/ships/bb62/p1010024.jpg
>
> So how did things actually work??? I've got these items installed with
> my TTY gear - now I just need to find a KW-37 crypto unit at Dayton or
> Fair Radio next week - ha!
>
> thanks,
> Nick K4NYW
> www.navy-radio.com