Is it possible to determine whether a phone call is local or long distance by analyzing the audio?

Circa 70's, era of 'Kaptain Krunch" *if* the call were made 'inside' the office switch range, the bandwidth is incredible.

For example, across Silicon Valley, we could routinely send 10kbits/specd, and higher, using a modem with a simple wquare wave the bandwidh was so good! But if linked into carriers and trunkines that bandwidth was stripped to a standard 300-3kHz bandwidth, with a 4-6 pole cutoof, and could NO longer use the modem waveform system.

It is my undertanding that now the equipment strips the bandwidh no matter where.

PS: I met, worked with the guy, that made/sold those infamous "Blue Boxes" that enabled you to call around the world for free. He is a convicted felon and spent 1 year in jail. I asked him, "How do you call for free?" He said, "*IF* I tell you , I will be committing a felony. and *IF* you listen, YOU will be committing a felony." That's when I learned that because he had been so severely punished AND there were so many laws affecting citizenry, that the streets were SO much safer at night.

What is the purpose of this exercise? Bill O'Reilly obviously was in Dallas. Why would he be talking about getting a flight if it was a local phone call?

While the blue colored were the most famous, they actually came in more colors than M&Ms (or the candy Macintoshes).

I read somewhere that phreakers Jobs and Wozniak even phoned the Vatican, claiming that the caller was the president of the US. Some Cardinal was summoned and they had to hang up quickly.

-Ramon

You forgot red. Black was easily defeated by the CO (e.g., moving to ESS). Red and Blue were, by far, the most "useful".

Yes, but I'm not going to get involved in a conspiracy theory resurrection.

In the 1970's all long lines telephony was analog. There were channel bank filters and mixers that upconverted base band audio to higher frequencies for transmission, and back down at the destination. Also known as FDM (frequency division multiplex: The conversion process is not perfect and it is possible to see mixes and intermodulation products of the carrier and local oscillator frequencies of this up/down conversion process on the resultant audio[1]. There was also about a 1 to 5 Hertz Bode frequency shift introduced to prevent feedback and oscillation. You can't hear the beatnotes and frequency shift, but you can see them with PC based spectrum analysis. I suggest: or better yet Spectrum Lab: You will need to look at the "blank" spaces between the words, where there is no voices or background noises to muddle the display. You're looking for continuous carriers, buried well under the voices. Autocorrelation: is a big help for seeing these tones by removing the audio and background rubbish.

Interpreting the residual tones, and separating them from recording artifacts, is going to be difficult. You'll need to find someone with experience in 1970's telco muxes as well as some clue as to where these recording have been, whether they were converted from previous recordings, and possibly what equipment was used. You'll also need to know which CO handled the call, which will point to which carrier handled the call (AT&T, GT&E, ITT, etc), and then what brand and model of carrier equipment might have been used. That's not going to be easy and will probably be a huge time burn for little benefit.

Hopefully, I've given you enough hints to get started. You're on your own. Don't bother sending me email as I won't help.

If you cannot figure out a possible rational explanation, then you are LOST.

Just like e-mails, ALL OF IT can be faked. Or any combo. Name, number, voice, sound real or sound recorded, static, backgrund sounds, etc.

That's no revelation, Bob: The younger generation has no idea that something called "Usenet" even exists.

A few years back, it was possible to access it for free (via Google Groups) and post links to it (which is essential for its survival).

However, with their new interface, Google inflicted yet another wound to Usenet. Being a pioneer and co-founder (along with a DeMillean "cast of thousands") back in my days at MIT, it saddens me.

Best regards,

-Ramon

Showing my age here, but the Blue Box stuff happened when I was an undergrad. One of my buddies heard that it was all based on an article in some Bell Labs journal that divulged the trunk access tones, and also heard that Bell was quietly removing copies from college libraries. (This was before the Internet, of course!) Anyway, he guessed that they may not have gotten to the backwaters of General Motors Institute, so he checked... bingo!

So now, somewhere in my files, I no doubt still have my copy of said infamous article. I never tried to put it to use, however... heck, I didn't know anybody far enough away to need long distance calls!

Best regards,

Bob Masta DAQARTA v7.60 Data AcQuisition And Real-Time Analysis

On a sunny day (Thu, 12 Mar 2015 08:28:30 -0500) it happened Ramon F Herrera wrote in :

Nice to hear you were part of that. I did notice that some years ago universities were the first to switch off their servers. There are still many free news servers where you can post too, aioe.org being a well known one. I sometimes use google to backtrack to an original posting.. Google is not really Usenet, and they named it 'google groups' on top of that. I wrote my own news reader in 1998 or so because there was no Free Agent for Linux.

Right. ALL the required information was in the public domainn.

What caused it to 'hit the fan' that the playfulness got out of hand. The people would 'stack' trunk lines in and out of cities, then call ATT 'inspector' employess like at 2:30 am and say listen to this, then hang up and the now wide awake victim would listen to the clicks as each trunkline relinquhed, click, click, click, ... sometimes stack 20+ That was 'playful' irritation, but what really brought down the rafters, was a group stacked trunklines in and out of Salt Lake City, essetially isolating it completely! With the potential of emergency calls being shut off [and perhaps some were shut off], the govt stepped in and stopped it all. [that's my understanding] Yes, you can find a small reference to the isolation occuring in the public domain as a general news media blurb. I remember the announcement, but not attaching significance to it, until I met ?? and he told me about the incident from an 'insiders' point of view.

Not MIT! The server news.mit.edu was one of the first, most active and it is still around. See here:

(scroll to "Usenet")

-Ramon

On a sunny day (Thu, 12 Mar 2015 10:19:53 -0500) it happened Ramon F Herrera wrote in :

Good to hear!

The flaw in the *practice* of most phreaking was: who are you going to *call*? A stranger? Call a relative and you risk TPC later contacting them and inquiring as to who they *received* the call from. What *stranger* are you likely to call and chat for a significant amount of time? ($$)

In certain exchanges, TPC would install traps on all the lines just for that reason.

And, getting caught with a "box" was sort of hard to explain ("Oh, it's a miniature *organ*! I use it to play music while riding the bus... Yeah, I know it sounds REALLY CRAPPY...")

I'm not sure it was ever considered /prima facie/ evidence -- but anyone aware of that sort of crime (campus!) knew what it meant! E.g., in many jurisdictions, possessions of lock picks (without a license) is evidence of a crime.

Another prevalent hack was the annual publication (in _TAP_) of the "eagerly awaited" credit card code. This has the advantage that you could keep it in your head and achieve the same results as carrying a box on your person (effectively, a "red box in your head").

If anything is proof of the futility of "security by obscurity"...!

On a sunny day (Thu, 12 Mar 2015 16:06:15 GMT) it happened Jan Panteltje wrote in :

But but but.... panteltje12: ~ # telnet news.mit.edu 119 Trying 18.181.0.25... Connected to news.mit.edu. Escape character is '^]'.

panteltje12: ~ # telnet news.aioe.org 119 Trying 94.75.214.39... Connected to news.aioe.org. Escape character is '^]'.

So what good is it? ;-)

It was never open to the general public. They are understandably very protective of their bandwidth, which at some point was unbelievable.

There used to be mailing lists called LISTSERV based on IBM mainframes, ours at Yale. At the time a student friend of mine got his PhD in Computer Science, had to return to Venezuela and bequeathed me the administration of the list, which grew considerably. Recall that in the early 90s there were coups and tons of rumors down there. Friendly employees of the two main Venezuelan newspapers sent me the news nightly, plus a cousin who worked for IBM in Caracas (in theory it was only for IBM customers). The 3 were violating rules. We had a mailing list in which a magazine was distributed in *Postscript* with pictures, fonts, etc.

Some presidential candidate (later, president) came to Harvard and his staff (later, cabinet members) were patronizing us:

"Oh, I brought a copy of 'El Nacional' and 'El Universal' of today. I am sure you youngsters would like to read it!"

I told him:

"Abdon: We receive both newspapers, and distribute them all over the world, the *previous* night, before it gets printed."

and showed him the Postscript magazine. His jaw dropped.

We were using about 10% of MITnet traffic. One day Jeff Schiller (MIT main network guy) told me and my buddy Hector:

"Guys, why don't you make your lists distributed? For instance, the Brazilians have a server for the West of the US and another, here at MIT, for the East of the US".

We ignored the kind advice, and in fact I decided to do the opposite: The subscribers in Europe, Russia, etc. were attended by a sub-list in France. I told the girl in charge "Hand over the list, the whole thing is going to be based at MIT".

Fun times...

Oh, speaking of unbelievable bandwidth. One day my boss was notified by his (Cecilia D'Oliveira):

"Jeff, pack your bags, you are go "Well, we are go "Makes sense. Approved".

Good times...

-Ramon

I forgot the must fun part:

"Abdon: This is the magazine that you will read *next* month in Caracas".

HP had recently moved from 300 dpi to 600 dpi and MIT has the laser printers before they were available to the general customers. It took us a while to get the double side working properly.

Then Digital Equipment (founded at MIT, circa 1957) gave us advance hardware (RISC DECstations). Until then, silly me, I had no idea that hardware also has versions (1.0, 1.5, etc).

-RFH

I posted this question in the Stack Exchange Forum:

and was asked for an "Audio Corpus".

It is here:

In one of the audio clips, I removed some of the background noise, most likely caused by Fonzi's tape recorder.

TIA (again),

-Ramon

Good ole red box. RadioShack 33 number auto dialer. Change the crystal to 6.55 mhz and 0 was a nickel.