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Fiber Optic Spying: Newsletter Challenge (12/05/06)

Posted December 03, 2006 5:01 PM
Pathfinder Tags: challenge questions

The question as it appears in the 12/05 edition of Specs & Techs from GlobalSpec:

Your devious friend wants to listen in on your next-door neighbor's phone conversation. Your neighbor's phone line is running on optic fiber, and your friend claims he knows of a way to listen in without cutting the fiber. How?

The answer to this questions will be revealed in the 12/12 edition of Specs & Techs. Click here to receive Specs & Techs via email.

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Anonymous Poster
#1

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/04/2006 2:12 PM

Hint that he should invite you over to dinner, and plant a wirless transmitter in the phone reciever/earpiece.

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#2
In reply to #1

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/04/2006 2:49 PM

bounce a laser off his window

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#3

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/04/2006 10:48 PM

One way:

use a refractive tap. By carefule choice of silicone fluid you can affect the glass/air interface so that some of the totally internally reflected signal can exit to a detector you have placed on the line.

This will only work if you can get at the fiber and only cause a small loss in end to end signal

Another way:

If you have access, make a small radius bend in the fiber. This will cause some signal loss, which you detect. Take care to not break the fiber or cause too much loss.

Both of these will take some experimental work to perfect.

A third way:

Cut the line and install a bidirectional powered repeater/splitter take care you emulate their expected signal. Phase shift detectors will ferret this out, so take care.

In both of these a wise IT department will send end to end pulses and measure the loss and may detect your tap if it causes too great a loss.

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#6
In reply to #3

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 1:48 AM

You are absolutely correct. The rude guest is just that, rude and possibly ignorant of the technology.

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Anonymous Poster
#24
In reply to #3

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 7:31 PM

The process is called 'frustrated total internal reflection'. A light beam's E-M field extends a short distance outside the glass fiber's surface and can be 'tapped' if a similar refractive medium is placed in very close proximity. Physics students do this as an optics lab experiment, at least we did in the sixties.

http://en.wikipedia.org/wiki/Total_internal_reflection

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Anonymous Poster
#4

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/04/2006 11:01 PM

tell the neighbor to get a life. blackhawk 44

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Anonymous Poster
#7
In reply to #4

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 2:20 AM

Tell him, furthermore, that you have no intention of detaching your own line to insert a tap; or of dialing your neighbor's number, thanks all the same!

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Anonymous Poster
#5

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/04/2006 11:27 PM

Well unless it is fiber all the way to his phone just tap his NIDS box on the outside of his house. and be thankfull your electrician put yours on the inside even though your provider was pissy about it

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#12
In reply to #5

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 11:18 AM

As I understand it (and my understanding is pretty incomplete, partly because I have copper coming to my NIDS) the fiber goes into the house, and is only converted to wire signals there. I'd be interested in knowing (from someone who works with fiber installations) how the signal is distributed in the home. For example, are fully fiber phones on the way? I gather that modems have fiber inputs, but wire outputs, and that routing is done as it is now: wired or wirelessly. Can someone explain, or provide a link?

For the really nit-picky among us: I suppose using fiber into homes shifts electrical load onto the consumer, and away from the telco. Although today most phones have a power supply brick for one reason or another, in the old days all the power for amplification and ringing came from the phone company.

There seem to be fiber couplers available that will split one fiber signal into two. I assume the assumption for the question is that you do not have access to any terminations?

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#13
In reply to #12

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 11:42 AM

Previously being a "phone-man" for 12 years (the last time that I worked on telecom equipment was 1997-so I'm kinda out-of date) I worked on a T-1 line that was fiber-optic to the telco equipment but it was all twisted pair copper to the demarc. I was installing a T1 demultiplexer. As far as I know Telco still supplies the ring voltage: 85 VAC and the line (tip/ring) voltage -48V. The power supply that goes to most phones these days are to power the cordless, speaker, answer-machine etc. I have never seen in-premises fiber optic installed by the phone company (in the USA, that is.)

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#14
In reply to #13

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 12:31 PM

My question about power for ring and amplification might have been unclear, and is also based on assumptions that may be complete nonsense. I am guessing that when a fiber line is brought into a house, the copper line is taken out, and that there is no longer any copper connection. (I think I read this somewhere.) If that is the case, then ringing and amplification would have to be supplied by the customer's power source, I think. A couple extra milliwatts is hardly going to break the budget, but it's interesting to know where the power comes from. If my understanding is correct, then in power outages, you'd have no phone service. That seems problematic -- so maybe my assumption is haywire.

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#15
In reply to #14

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 12:42 PM

I guess that I misunderstood. Yes it would seem that a fully fiber-optic cable equipped house/ business would have to rely on the customer's power. I've never heard of this, though. Do you know of such an installation? What kind of phone jacks to they use? RJ-11's wouldn't quite do the trick anymore..

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Anonymous Poster
#17
In reply to #15

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 1:36 PM

I have fiber to my home, but it changes to CAT 5 (copper for high band width) in the home. RJ-11's do not work with these. You must use RJ-35 (or RJ-38). These are slightly larger than RJ-11.

Now to the question: forget the fiber & tap into the copper wire. This can be done on the outside where the fiber to copper transition is made.

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#20
In reply to #15

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 4:12 PM

Here's a good article by someone who recently had fiber installed. The conversion box has house ac hardwired to it. In the article, a backup battery is also mentioned -- so that addresses the power outage issue, I guess. Looks like putting fiber in is a pretty big deal.

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Anonymous Poster
#8

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 2:30 AM

Maybe...??...it would involve beaming a known (repeating or otherwise) signal across the fiber at normal/large angle; detect the interference pattern on the other side; decode and extract the orginal conversation from the "optically multiplexed" fiber-tap output signal.

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#23
In reply to #8

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 6:55 PM

They wil not mix = no heterodyne, as you need a non-linear media.

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#9

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 3:28 AM

Steve-o had the answer - you bounce a laser off the window of the room with the telephone and then decipher the modulation on the received signal.

You could also use a very sensitive wide band radio receiver which will pick up any audio modulation from electrical equipment in the room. The invertors on low voltage and fluorescent light are favourite as they emit low power VHF signals and it is easy to pick up the modulation. You can also pick up modulation from the PC or TV set - even the mouthpiece of the telephone and the cord to the fibre optic transmitter will radiate a useful signal. This will of course only give you whats being said - not heard from the line but you could probably work out the gist of the conversation.

How sad that we feel the need to spy on our neighbours!

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#10
In reply to #9

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 5:04 AM

It would seem that several posters don't quite get it. This is a hypothetical question. It constitutes a learning exercise. If you are offended you are free to not comment and let those of us who care to engage in such educational and entertaining activities do so without clueless holier than though judgment and heckling. Perhaps it is you who has nothing better to do.

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#11

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 10:42 AM

It's apparent the devious friend works for the Bush administration.

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Anonymous Poster
#16

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 1:32 PM

Its quite simple really. You use some espionage action to sneak into the house and then you just listen in on one of the other phones. No need for high-tech devices, just good old fashioned trespassing.

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#18
In reply to #16

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 1:39 PM

I think that the military has a flying spy robot the size of an insect that has a camera and microphone..

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Anonymous Poster
#35
In reply to #16

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 10:03 AM

How about the old-fashioned glass or stethoscope against the wall.

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#36
In reply to #35

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 10:06 AM
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Anonymous Poster
#19

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 3:59 PM

Question:

The question as it appears in the 12/05 edition of Specs & Techs from GlobalSpec:

Your devious friend wants to listen in on your next-door neighbor's phone conversation. Your neighbor's phone line is running on optic fiber, and your friend claims he knows of a way to listen in without cutting the fiber. How?

Answer:

Light transiting either multi-mode or single-mode fiber,will exit any non-light shielded fiber when this fiber is bent such that the light's angle to the core/cladding at the bend, exceeds the critical defined by Snell's law.

Once the light is detected from the 'bent fiber', the light data protocol then can be analyzed, multiplexed for the specific 'data channel' of interest -- DS-0, IP, etc.

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#22
In reply to #19

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 6:53 PM

Yes, That was one of the methods I mentioned. The grease changes the angle and with the right grease you can get an exit beam with zero bending. Just make sure you only cover a tiny spot or the attenuation will be noticed. same with bending, too much = high leakage rate.

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Anonymous Poster
#21

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/05/2006 5:44 PM

There has to be a transition from analog to fiber. Simply tap into the line ahead of the transition using conventional methods. Cheap and dirty.

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#25

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 1:25 AM

My personal opinion is that trying to tap into a fiber optic cable is somewhere between impossible and forget about it. Think about it for a while, you would need to remove all the shielding, insulation and armor without damaging a strand of glass that is only the thickness of a human hair. You just couldn't do it.

That means the most likely place to break into the signal would be where the fiber terminates and the signal reverts back to copper other wise known as the Optical Fiber Termination (OFT).

Picking up a signal from the OFT could be achieved is several ways for example

Pick up and monitor electro magnetic radiation from the OFT.

Tap into the signal with a physical link at the OFT

Standard bug connected to copper cable or phone

These could all be achieved with any number of commercially available devices.

The simple answer is tap into the signal after it reverts to copper and leave the fiber alone.

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#26
In reply to #25

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 1:31 AM

I am not so sure that the CIA or KGB(or whatever they call themselves) would not do this.

There are precedents. The CIA tapped into russian underwater cable.

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#27
In reply to #26

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 1:47 AM

Yes they did but the cable they tapped into was coaxial copper cable not fiber optic cable and the Russians found out about it. Fiber optic cables have several layers of armor all of which are many times thicker and robust than the glass fiber they protect. Striping all this off when you are terminating the cable is an art form so trying to do it mid cable without breaking the fiber just doesn't seam feasible. I have never heard of anybody having ever successfully achieving it. Does anybody know if this has ever been done either in the laboratory or field?

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#31
In reply to #27

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 8:23 AM

would we ever hear of successful fiber taps?

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#32
In reply to #31

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 8:35 AM

Anonymous guest #30 seems to have several ideas on how to do it. Secret government agent man?

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#45
In reply to #25

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/12/2006 7:43 PM

Masu, six more and you will have GURU status.....Is that why the eyes are bloodshot?

Mmmmm. Quantum Paired Photons.....End of a Problem that really was never as you so correctly pointed out was much of a problem in the first place.

An alternative would be to use a Ron Rivest, Adi Shamir, Leonard Adleman Dual Prime Composite Type Open Key Cryptographic approach. but don't think the Bank's 128 bit Dual prime is at all secure, It is not.

All you need is a little patience and a half decent Arbitrary Precision Calculator. It is not hard to factorise a large dual prime composite if you can establish a 'monotonous' algorithm. Quite easy really.

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#46
In reply to #45

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/12/2006 8:00 PM

Postscript:-

The first 'asymptotic' monotone algorithm will invariably 'diverge' so you will need a second 'super-asymptotic' monotone algorithm, if you ensure a 'harmonic' match to the second monotone, you will probably? avoid needing a third 'harmonic' or hyper-asymptote, my calculator is only 5000 digits, I probably need a bigger one to test that theory.

Remember a dual prime composite is just a blooming simple rectangle after all. Two similar rectangles 'P.Q' x 'p.q' will make a pseudo-square, the 'p.q' need not even be a prime composite 'P.Q' x 'x.y' would be more correct. or P.y.Q.x as we know a perfect square will always yield a cardinal integer as it's square root, and a pseudo-square composed of primes will never do so, but as it becomes more square and less pseudo, the square root will asymptotically converge to a cardinal number either 123£%^$$^^*...............89995688.999999999964758 ...or 758586586.49999999778 if one of the 'x' s or 'y's is an even number.

Slightly off thread but intended as a CAVEAT for those interested in secure electronic telecommunications traffic.

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#47
In reply to #46

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/13/2006 2:33 AM

I can't say that I am that happy with the official answer to the challenge. As they pointed out themselves both solutions require the removal of the sheath without damaging the fiber within. Whilst not impossible it would be next to impossible to achieve in the field.

If you read the information about how the installations are done ( link in post #20 by Ken_fry) you will see that any routing is done either at the exchange or the Fiber Optic Termination unit. As I posted earlier that means everybody on a particular fiber subnet must see all the information that travels along that particular subnet. All that is needed is a passive FOT addressed the same your neighbors on the same fiber subnet and bingo you have all the traffic into an out of his house.

As you have pointed out Alistair, cracking the code isn't that big a problem and given time with the power of today's computers I would expect it could certainly be achieved in a reasonable time frame.

Personally I like my idea better than stuffing about with fiber optic cable, it would certainly be a whole lot more covert.

PS. The reason I turned blue in the face and my eyes are bloodshot is either due to the rising levels of CO2 in the atmosphere or from talking till I am blue in the face to people in other threads that just don't want to listen. Shyam suggested that it could however be confused with a Doppler shift due to an expanding or contracting universe but conversely could be from me running away at near light speed form dead end threads and back to intellectual ones.

This post by the way makes me a GURU but I am unsure of this weather this is an indication of dedication or being deranged. Please feel free to make your own interpretation.

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#49
In reply to #47

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/14/2006 5:20 AM

You have my commiserations 'masu', So often an intractable problem has a very simple solution. I think it was a lecture given by Adi Shamir? who pointed out that Criminals bypass security, rather than bother to crack it. Just wait till the safe door has been unlocked by the Bank Manager, and then put a fire-piece to his head. Criminals are 'cunning' and very seldom 'intelligent'. Sending them to jail, is a bit like sending them to the University of 'Cunning'....They come out with a degree in criminality.

Criminals were hampered for a time by the 'CATPTCHA' protocol, intended to prevent non-human 'information-trawls' by automated software. Most folk are familiar with having to read some 'wonky' letters and being asked to type them into a box exactly as seen....blah.....The Crims then got on to their 'Porno-Pic & Gambling' racket fellow travellers.....and divert the 'CAPTCHA' at the speed of light to some unsuspecting 'punter' who promptly types in the 'wonky' letters just in time for the 'hacker' software program to download all the details. "The Man in the Middle Attack"...tut tut.

We have been working on some very neat solutions.... but the best of them require that Registered Snail-Mail...sets up the security protocol. You have to ensure the criminal 'Gives Up'.....The way to do this is [a] make it very hard for him/her, [b] make the probability of detection very high and costly to the crim.

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Anonymous Poster
#28

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 5:06 AM

There is still another option here. So far the discussion has neglected the other end of the cable: the phone company side. There are often junction boxes which are very accessible to alternative entry and usage. The clever operator may even be able to direct the signal back to the friend's line without detection.

Someone at the phone company could also be bribed.

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#29

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 5:54 AM

Fiber optic networks have enormous bandwidths, far greater than any individual building would need. To utilize the network efficiently it is organized in a fashion similar to Ethernet where every packet of data that a particular machine or node receives or transmits being broadcast over that particular subnet. Now if both you and your neighbor both have fiber connections to your houses then it's a pretty safe bet that you will be connected to the same subnet.

This all means that the packets of information being sent to and transmitted by your neighbors phone will be broadcast over the same subnet you are connected to. That means if you had the appropriate equipment you could monitor this traffic without being detected. The easy bit is the interception part, the hard bit would be knowing how to decode the data as it could use some very complex encryption algorithms.

The upshot is if you have the equipment you don't even need to go out of the front door of your house to tap the phone in the house next door.

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#30

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 8:02 AM

One method of snooping on fiber optic cables is to remove a section of the protective cover and run a strand of similar fiber optic material next to the strand to be monitored. A small amount of light will transfer and that can then be monitored with suitable equipment. An alternative approach is to access the wire to F/O box and install a transmitter tapped into the wires prior to the conversion. The third method is to use a radio receiver tuned to the clock frequency of the audio to light encoder and decode the signal. This method works well enough that the government demands extra shielding on much of the communications hardware.

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Anonymous Poster
#33

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 9:03 AM

While the phone service to the home is fiber, the "Smart Jack", usually on the outside of the house, is normally copper wire (Cat 3 or Cat 5). With the proper handset (or just another phone if Cat 3), you can plug into the Smart jack and hear all.

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#34

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 9:57 AM

Once again the challenge has asked for an answer that while possible is totally impractical. Sure you could dig up the cable, manipulate it so you pick up on some transmission loss, and record/convert the data into speech. But think about it. There you are, digging a hole in a neighbors yard, stripping a cable, and hooking up some equiptment to at least record the data so you can convert it later. Dont you think someone might notice you? Same thing goes for tapping into a junction box where the fiber/copper transition takes place...dont you think you'd get noticed standing out there with a handset listening in?

Picking up in the emf in the room sounds interesting, assuming you can filter out all the background noise. But, assuming you could get in the house to plant detection devices, why not just bug the telephone recciver and be done with it (then you wont have to go through the trouble of decoding the signal, since you'll be capturing the converted speech)

Bouncing a laser off the window will probably only get you half of the conversation (the neighbors voice)

If you could not gain access to the inside of the house, I would wait untill cover of darkness when the neighbor is away. I would sneak over and at the junction box (for lack of a better term) where the fiber optic/copper connection is made, I would tap the copper line with a small transmitter. You can usually find plans for such devices in the radio shack project handbooks, so they should be easy to fabricate. If you have line of sight with the junction box, you can use an IR transmitter, and if not, radio. Such a small device could be hooked up literally in seconds, limiting your exposure, and may even be able to be concealed within the junction box itself. Then you'd be there and back in a minute. You could then capture all signals on that line from your home, undetected. If you're lazy and dont want to fabricate your own device, take the circuitry out of a cordless phone base and hook that up, and then take the handset with you.

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Anonymous Poster
#37

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 2:34 PM

The proposed methods of tapping into fiber optic cables are interesting. However, the statement "your friend claims he knows of a way to listen in without cutting the fiber". Is merely factually correct. It does not logically follow that he is actually going to use the fiber to accomplish his goal. Therefore, to be practical and get the job done, I believe he will be using one of the proposed "conventional" methods.

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#38

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/06/2006 2:58 PM

PUT YOUR EAR ON THE DOOR OR WINDOW OF THE ROOM IN WHICH THE NEIGHBOR IS MAKING HIS PHONE CONVERSATION.

OR

IF IT IS A WIRELESS PHONE, TRY USING A SCANNER.

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Guru
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#39

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/07/2006 12:33 AM

Folks you are all going about it the wrong way. Keep in mind the fiber network as a shared network so all you need to do is intercept the packets of data sent to and by your neighbors Optical Fiber Termination Router (OFTR) and decode the data. You don't even need to outside let alone stuff about with trying to splice into fiber optic cables etc.

If you set up an OFTR with the same address as your neighbors so that it will only receive packets addressed appropriately it will intercept all the traffic too and from your neighbors house. All you need to do then is decode the data and if the cable people are doing their job properly this is the hard part not the actual taping of the line.

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Power-User
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#40
In reply to #39

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/07/2006 7:26 AM

Masu, You look different!

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Guru
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#41
In reply to #40

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/07/2006 11:19 AM

Yes, somebody else started using my avatar so to save confusion I changed it. I am told the original was too me to get rid of so I redrew it, changed the colour and made the eyes bloodshot. Do you approve?

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Power-User
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#42
In reply to #41

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/07/2006 11:24 AM

Yes, the bloodshot eyes remind me of me!

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Anonymous Poster
#43

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/07/2006 10:36 PM

Usernumber5 again

I'm sure everyone is about done with this thread But I have one more thing to add.

I have customer/friend that recently bought a recently shut down call centre for a phone company. It has a nice fiber input that will handle some thing like 3500 lines?

anyways after having a nice conversation with some of the building specialists I was told about a new system that is being worked on.

Homes will no longer have coper or fiber ran to them, each home will have a repeater system that will communicate local transmitter/reciever to accomplish higher data transfer and also has the ability to be monitored from up above yep there going to make it even easier to keep tabs on us.

beware of the future its here

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Power-User
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#44
In reply to #43

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/08/2006 7:27 AM

Well, that's something to look forward to.

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Anonymous Poster
#48

Re: Fiber Optic Spying: Newsletter Challenge (12/05/06)

12/13/2006 11:00 AM
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