News for hackers. Stuff that matters.
Re:Air gaps never exist (2011) by peterwwillis on Friday December 04, 2015 @04:53PM (#10679425)
https://webcache.googleusercontent.com/search?q=cache:wZ0Cex...

http://www.gocsc.com/userfiles/file/ortronics/whitepapergovt...

https://security.stackexchange.com/questions/10447/is-the-us...

I'm honestly not familiar with these kinds of facilities, but with a potential "Collateral Confidential" type cable, one could imagine a gas-filled tube being a countermeasure of some sort.

Re:Air gaps never exist (2011) by jessaustin on Friday December 04, 2015 @04:58PM (#10679457)
For instance if the gas were poisonous?
Re:Air gaps never exist (2011) by inopinatus on Friday December 04, 2015 @05:10PM (#10679541)
More likely there is a pressure sensor, intended to detect splicing attempts.