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Identifying North American Phone Switches

96 pointsby doctorshadyalmost 9 years ago

8 comments

mindcrimealmost 9 years ago
I miss my phreaking days (the early to mid 90&#x27;s). Me and a couple of buddies would drive out into the middle of nowhere late at night, find a convenience store with a COCOT, beige box off of it, and use my shitty 486 laptop to dial into the telephone switch for the local telco (which we found via trashing). We eventually worked out the password for an account that had the equivalent of &quot;root&quot; privileges and for a while basically owned the switch. The problem was, we didn&#x27;t know how to <i>do</i> anything fun. We tried to do the thing we&#x27;d read about in that one Kevin Mitnick book, where you turn someone&#x27;s home phone into a pay phone (that is, configure it so that when they pick up the phone and dial, they get the &quot;please deposit $4.75 for the next 5 minutes&quot; message) but never could get the exact right commands down. Well, so far as we know anyway. If it worked, we never heard about it. I won&#x27;t say who the target was, to protect the guilty.<p>Those were the days... a 20+ foot phone cord stretched across a parking lot, and we&#x27;d sit there nervously looking for cars that might be cop cars, and try to figure out what we&#x27;d tell the cops if they stopped and asked what we were doing. But it was a rural area in the mid 90&#x27;s, so we figured most of the cops were so technology illiterate that they would have no clue about hacking&#x2F;phreaking or anything. At any rate, it (surprisingly, in hindsight) never came up.<p>There was a BBS we spent a lot of time on back then as well, from the 303 area code. I don&#x27;t remember if the board was named Voyager, or if that was the nick of the guy who ran it. Anybody remember them&#x2F;him?<p>Edit: Found it. The board was &quot;Hacker&#x27;s Haven&quot; and the sysop was Voyager.
Alohaalmost 9 years ago
&gt; * 5ESS line cards are pretty distinct sounding. They&#x27;ll make weird noises whenever you go offhook, have a slightly higher noise floor then most line cards, and a very strange frequency response. This doesn&#x27;t necessarily apply if you&#x27;re using a line served out of a channel bank or something, but the line cards can give a very different experience on the phone network sometimes.<p>5E analog line cards are (as far as I know) are all concentrated at one level or another (think 4:1, 10:1, etc) - which means there is an analog cross point switch to tie your line up to a codec - when your line goes into permanent signal, you&#x27;ll be linked up to what appears to be an analog announcement trunk, as to avoid tying up any of the TDM bandwidth on the switch.<p>Whereas DMS100&#x27;s are codec per line, and are not concentrated in the same way. I think GTD-5&#x27;s are also similar to the DMS and codec per line.<p>When you go off hook on a 5E you can her tick-ta-tick-tick-dialtone as it sets up the link thru the analog switching fabric - this seems to be universal to all 5E&#x27;s - the 5E2000 sounds different, and I believe uses different ckt packs to do the switching, but fundamentally appears to work the same way (I&#x27;ve not had a chance to sit on a 5E2000 line to get permanent signal to confirm that).
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throwaway8543almost 9 years ago
The details about being able to dial 0XX on some switches sounds scary. If I recall correctly, numbers starting with NPA-0XX and NPA-1XX were reserved for what essentially became network administrator functionality. These were ways to reach special telco operators, as well as testing equipment, either locally or across the long distance network.<p>Being able to reach this stuff is akin to bring able to talk to your ISP&#x27;s internal IP network. Given the continued restriction of this special prefix (your telephone number still cannot start with a 0 or a 1 after the area code) and the persistence of legacy systems on the PSTN, I would not be surprised at all if these codes were still in use.
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stevenhubertronalmost 9 years ago
This book is a great read and gives an amazing overview of the culture: <a href="https:&#x2F;&#x2F;smile.amazon.com&#x2F;Exploding-Phone-Untold-Teenagers-Outlaws-ebook&#x2F;dp&#x2F;B009SAV5W0?ie=UTF8&amp;btkr=1&amp;ref_=dp-kindle-redirect#navbar" rel="nofollow">https:&#x2F;&#x2F;smile.amazon.com&#x2F;Exploding-Phone-Untold-Teenagers-Ou...</a><p>The group chats must of been so cool at that time.
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lowglowalmost 9 years ago
I think I hit the tail end of phreaking, most of the exposure I had was through text files downloaded from BBS&#x2F;FTP sites that relayed the knowledge of building &quot;boxes&quot; with such colorful names as &quot;blue&quot;, &quot;brown&quot;, &quot;rainbow&quot;, and &quot;piss&quot;. The phreaking I knew moved from land lines (of which I only participated in &#x27;beige-ing&#x27; from a neighbor&#x27;s line, and I won a lineman&#x27;s handset [thanks #303&#x2F;cuervocon] ), to cell phone cloning, bridges, and the occasional digital switch. Less analog hardware, more software&#x2F;digital systems. Nostalgic!
coldpiealmost 9 years ago
Having been born in the late 80s, this is before my time. But there seems to be a lot of fondness in hacker culture for phone phreaking. Frankly it seems almost out-sized: it even got a cameo in Pirates of Silicon Valley. So, why was this such a big deal? My perspective on it was just a way to get free calls from pay phones; is there more to it than that? How important&#x2F;expensive were these phone calls that it became such a widely known technique? Is it just admiration for an early, and neat, hardware hack?
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fapjacksalmost 9 years ago
Lucky225 and Evan Doorbell (two contributors mentioned at the bottom) are pretty legendary phreaks. Probably they all are awesome people, I just know of those two. Evan Doorbell has an amazing collection of audio, if you&#x27;re interested in this kind of thing.
astruttalmost 9 years ago
Discussion is ongoing @ irc.2600.net #telephreak<p>Awesome write-up! thanks!!