Hacker Newsnew | past | comments | ask | show | jobs | submitlogin
An Open Letter from a Phone Phreak (pastie.org)
7 points by doctorohhnoes on Oct 15, 2013 | hide | past | favorite | 7 comments


I should probably add that the circuit switched stuff really isn't incompatible with less obscure gear. You can even send raw TDM frames over layer 2 ethernet. There's an implementation in PBX software for this.

http://www.thrallingpenguin.com/articles/tdmoe-mf.htm


Its sad that we are regressing from high quality to low quality voice telephony. Telephone companies are already petitioning (rather silently) to remove any aspect of regulation from the state utility commissions. I got a tattered postcard in fine print from CenturyLink explaining about such a hearing that will take place in .. get this .. 4 days on a weekday. I suspect they don't want the public to be very aware of this.

Soon, the last saviors of communication, the battery bank powered analog telephone line with cold war reliability, will be replaced with garbage DSL/VoIP modems that crash on a daily basis with choppy audio... yay.. i can't wait for another actiontec. This is going to be the replacement for the "landline". Seriously.


That's assuming they'll provide it at all. I'm assuming if they get someone to overturn universal service regulations, some rural, less profitable communities may be deemed not worthy to keep providing service in at all.

I'm sure just the idea makes the cable companies feel all warm and fuzzy.


Do black/red/blue boxes still work or is there a current generation of similar type phreaking devices?


Blue boxes? To some degree, yes. There's a lot of switches in rural areas that rely on MF signaling (usually the ones that don't offer caller ID or anything), but they don't use 2600 hz supervision like the old carrier systems do. They use bit-robbed signaling. So to be able to send your own MFs into a trunk, you need to be able to fool the switch into thinking the trunk just hung up and went back offhook.

Internationally, it's a different story. E1 carrier and it's derivatives don't support bit-robbed signaling, so you'll still find a lot of C5 trunks. 866-284-3437, for example, takes a very strange route (MCI to New York, and from there, we believe Paetec/Windstream abroad) before sending you to a conference system in Malaysia.

There's even some really strange stuff in rural Russia that actually relies on their own flavor of backwards MF. So if you send a 2600 hz tone and a single MF, it'll spit MF back out at you. In Soviet Russia...

As for red boxing? Yes, sort of. Most payphones these days run off of a microcontroller inside the phone, so there is a way to fool the phone, but it doesn't involve any kind of inband signaling. Some of the older ones are 6502 based if you can believe it. The Nortel/Quortech Millenniums, one of the more common phones, run on Z180s.

Anyway though, if you can find a phone that hasn't been retrofitted with a processor, you can place a call to some in-state long distance areas, and a TOPS switch (in short, DMS-100 family software) will listen for redbox tones to bill for the call.

As for black boxing? The short answer is no; this relied on a quirk in electromechanical stuff where you'd actually be connected to the called party while their phone was ringing. The long answer is, less and less no actually. One of the things I learned recently is if you're calling somewhere on an AT&T trunk that terminates over a 4ESS to a 5ESS before hitting your destination (in short, most large areas), you can pass audio before the calling party answers, and it'll let the call go on forever if nobody answers. So if you can find something that bridges two calls together without making the call answer, yes, you can effectively do the same thing as black boxing.

As for devices, these days it's about being as resourceful as possible. So the greatest things you'll find tend to be using just a regular phone and your wits.


Thanks for posting this. I love reading about the telephone networks and how they've grown over time into the mess of VoIP we all interact with every day.


Glad you enjoyed reading it :) . That's the point, though; the phone network predominantly doesn't run on an IP network now, and I feel we'd really be better off keeping it that way.




Consider applying for YC's Summer 2026 batch! Applications are open till May 4

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: