[Milsurplus] red/black TTY shipboard question

[Nick England]

Many many thanks, Mike - that's exactly the sort of info I was looking
for to understand how this switch was used in practice. I understand
the equipment OK, but never was involved in any operations when I was
working for NAVELEX - I worked in a lab except a couple of times
installing some stuff at the shipyard.
cheers,
Nick K4NYW
www.navy-radio.com

On Tue, May 8, 2012 at 11:13 AM, Mike Andrews <mikea at mikea.ath.cx> wrote:
> On Tue, May 08, 2012 at 10:39:42AM -0400, Nick England wrote:
>> 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?
>
> Let us suppose that you're getting ready to set up an encrypted circuit.
>
> You start with the crypto gear switched out of line, so that it's your TTY
> to the TTY at the Distant End (DE), with a bunch of other gear in between
> that is transparent when (and if) it works.
>
> You verify that you will be using keying material setting X on your
> receiver and his transmitter; this is easily and safely done in the clear.
> You set up your receiver and tell him to start his transmitter when he is
> ready. Now the circuit from him to you is secure, and he tells you to use
> keying material setting Y on your transmitter. You ack that, he tells you
> he is ready for you to start your transmitter, and you do so. You verify
> that the circuit is good both ways in secure mode and turn it back to the
> operators.
>
> If the circuit is, say, from Japan to Hawaii over HF, then when the techies
> can't find a good freq and the propagation sucks, you can wind up doing
> this every 5 to 15 minutes on a bad shift. I have a whole walk-in closet
> full of those T-shirts. Shorter-haul microwave circuits are a whole lot
> more stable, but we already knew that.
>
> And sometimes you may want to use a spare channel as an cleartext chat
> channel for debugging things -- hardware issues or, as I found myself doing
> once, personnel issues. I was TDY to ROK, supposedly to fill a critical
> personnel shortage. They had me cleaning and adjusting weapons in the
> armory, and then mowing the $%^&*( lawns.
>
> This didn't indicate a critical personnel shortage, so I got on a spare
> (unencrypted) channel back to my home unit in Japan, got my shop NCOIC on
> the other end, and we discussed what was going on. The next day I was in
> the comm center, doing what I was sent to do, and someone else was mowing
> the $%^&*( lawn.
>
> And yes, I think you are right w.r.t. the "Caution" legend on the UNCLAS
> indicator: don't open a BeadWindow, to use more recent terminology.
>
> --
> Mike Andrews, W5EGO
> mikea at mikea.ath.cx
> Tired old sysadmin
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