[ThoughtPhreaker]

Okay, so here's a skill I've been working on for a little while. It seems to be pretty effective so far, so I thought I might share it with everybody else.

It sounds like a pretty daunting task, but telling the difference between switches by the sound of the ring is not only fun, it's pretty useful. There can be times when the switch you're calling/dialing from is listed incorrectly on a lookup site for switch info, or you might simply be at a phone that isn't near net access, and need to know what kind of switch you're using to do something such as fool the restrictive dialing equipment. Or, you could just want to know it for fun. Whatever the case, before we try this, anybody who wants to try this from their cell phone may as well stop reading here. Yeah, sorry, as far as I know, this trick only works if you're using a decent codec, such as uLaw.

Right, then, let's get to the calls!

If you're looking for a place to start, calling a DMS-100 or 5E is probably the easiest way to get a feel for two different rings. Not only do they sound very different when you listen closely, this is going to be the most useful, since they're the two most common you'll find out there in the network.

Ready? Okay, let's call a DMS. 206-296-0001. I'm a little nervous about giving out a number that rang out when I called it during a scan, since chances are, it's going to be something, but it was in a block full of test numbers, and, well, if you'd prefer to find your own number that rings out, then go right ahead.

Anyway, though, can you hear that distortion in the ring? If you can't, it's no problem. Move the earpiece back and forth in whatever way is most comfortable and lets you hear the distortion best. It's usually a little hard to hear if you have the receiver too close.

Compare the same thing, only on a 5ESS; 206-236-0004 . It has sort of a "grinding" noise that warbles in and out, doens't it? If you've seen a 5E ring in a program like Cool Edit before, you'll probably know what I'm talking about. The waveform will move up and down in sync with the warbling noise.

Those are the two main ones. Here's a few other switches you might come across

This number is to a Protel 2000 on a Stromberg-Carlson DCO in a little town that couldn't be described better than the middle of nowhere. I *think* it accepts incoming calls, but consider yourself lucky if there's anybody around to answer it. In this particular place, it's almost literally dead silent most of the time. Not a single person on the streets. The modem will pick up if you wait long enough, but it takes a good minute or two, so it's easy to get a feel for the way the DCO ring sounds in the meantime. 503-633-9921 . If it's busy, or you don't feel good about calling a number people will actually answer, here's it's twin, and the number to a time machine in the same neck of the woods that'll ring twice before it answers.
503-633-9951
503-266-8463

To sum up the sound of DCO ring, it has a distortion like the kind DMS ring has, but it has more of a muted quality to it, and the distortion is more definite.

If you haven't heard of the airport discovery scan, then, well, shame on you. Take a good look over some of those numbers before you read any further :P .
http://dualisanoob.com/phreak/scans/airpor...covery.scan.txt

Seriously, check out some of the numbers on the Milwaukee EWSD, it's a great way to get a feel for the sound of EWSD ring. In a nutshell, it sounds almost identical to DMS ring, but it fades in and out, instead of turns on and off solid. If you've ever heard some cheap forms of noise cancellation, this'll probably be familiar to you.

GTD-5s have always been a little bit of a problem child for me to identify, and the ring, though semi-different from a lot of others, can still be a pain in the ass to distinguish from other switches. You can still hear the difference if you really see to trying, though. I guess the best way to describe it would be a mix between DCO ring and DMS ring; the distortion is pretty pronounced, but also has the weird noise the DMS does in the ring. I'll be honest, I've been neglecting my local GTD-5s a bit. It's up to you to find a number on one that rings. No big task, though, right? :)

There's a lot of other things to cover out there, like all the goofy obscure Redcom switches, and PBXes, even; those things are in a world of their own. I think it's just best to leave this where it's at, though.

For a few closing words, there've been times when this has actually given me pretty interesting results. A couple of weeks ago, I happened to be at an ACTS phone at the Seattle airport, and right as I picked it up, I heard two faint ticks before the dialtone just came on out of nowhere. Since it wasn't all loud and pronounced like 5ESSes usually are, I just decided it was a DMS-100. When I got local error recordings, or called the phone right next to me, though, it rang like a 5E. As it turned out, it was something I'd say is a little unusual. There's been a certain kind of relatively rare 5E linecard that I've only heard one time before. I don't know if this is third party equipment or what, but when you get pick up and get dialtone, it doesn't sound like a 5E at all. If I hadn't heard that ring, though, chances are, I'd never have found out it wasn't a DMS.

Oh, right, and before anybody asks me, yes, my real life has been a little slow lately. Why do you ask? :P

[operat0r]

wobble ring I can remember great post!