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Build Your Own Rotary-Dial Cell Phone
hwestiii writes "Yet another indicator of how unrepresentative of the main Slashdot crowd I am (meaning 'old') is that, like vinyl records, 8-track tapes, and Pintos, I can remember when rotary dial phones were items of everyday use, and not some object of retro-cool pseudo-nostalgia. Imagine my delight, then at finding this project in which an old rotary phone is turned into a cell phone. To give credit where its due, I originally found it linked from Hack A Day. I know nothing about home-built electronics projects, but this is enough to make me want to learn. If this catches on, imagine what they'll have to do to those 'turn off your cell phone' messages that play in movie theatres."
If, however, on the off chance you find yourself stranded in South English, Iowa, where the only pay phone in town is still rotary, this is how it works.
Pick up the phone and wait for dialtone. Insert a dime. (Yes, this phone still costs a dime!) Now, see the holes arranged on the disc? Find the one corresponding to the digit you want to dial, insert your finger, and rotate the disc clockwise until you hit the stop. Remove your finger. Wait for the dial to rotate back to its original position. Repeat as needed.
While you were dialing, did you hear those clicks? The circuit is actually being interrupted at a rate of 10 times per second. (This will be 20 times in some other countries.) The switching equipment in the central office measures the number of clicks and the time in between them to determine the number you dialed.
For more information, I suggest reading old articles of Phrack.
How am I supposed to fit a pithy, relevant quote into 120 characters?
Imagine how fun it would be to use this to send text messages!
People here in L.A. already drive badly enough with the current variety of cell phones...
......
Police officer:
So what caused you to rear-end that other car?
Rotary cellphone user:
I just took my eyes off the road for 15 to 20 seconds to dial a number and then
I've had my rotary phones ever since I moved out on my own. I like them, possibly because I an clumsy with buttons. My closest friends, however, are fond of mocking my choice as follows:
"Hi... yeah I'm over at Bob's place. I would have called sooner but he has a rotary phone."
Trying to use sarcasm in text-based forums does not work.
A quick trick of interest, perhaps good if you're ever in a situation where you can't use the dial pad and can't generate DTMF tones, is the super easy method of dialing a phone with nothing but the hangup switch.
On a mechanical phone (eg, any cheapo phone that doesn't need power or beep or anything), pick it up and listen for dialtone. Then just tap the hang-up switch with pauses for each number. For example, if calling 708-482-0623, you tap the switch 7 times, pause, then 10 times, pause, then 8 times, pause, etc. Rinse & repeat.
It's dirt simple, and most of us already know this, but... it's an easy fun thing to know.
10 times per what? Only if you're dialing a zero.
;)
As any old phone phreaker knows, one can dial any (land) phone - even today - by clicking the receiver. To dial a three, for example, one clicks the receiver three times (within a second).
If you don't believe me, pick up your house phone and try it. This once was useful information, in the days of rotary phone locks, but now is just more useless trivia cluttering up my brain.
If you're not living on the edge, you're just taking up space!
How come you say "dial" a number instead of push a number?
Anyone *really* old remember the letter prefix phone numbers? "Just call Zenith 4265. Operators standing by..."Insert witty comment *here*. I'm fresh out of wit...
Build it into a loafer thus having a genuine "Maxwell Smart" shoe phone.
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Hey, one good dated reference deserves another..
A goal is a dream with a deadline
Many years ago, probably the late 80's, I was at a restaurant in Vancouver waiting for a friend who appeared to be late. I was directed to the restaurant courtesy phone and was miffed when I discovered that the call from the restaurant to his home was long distance (Vancouver had some weird long distance rules back then, now fixed). Anyway, the courtesy phone had a long distance restrictor device attached so I pulsed dialed manually by clicking the receiver. All my tapping caused some curious looks from people in the restaurant waiting area, but it worked.
I believe digital switches are much less tolerant and "manual" rotary dialing will no longer work now on digital circuits.
Not at home, but I have one in my office at work. I found it in a cabinet and it was like finding gold; I had not seen or used one since I was about 8.
I took it into my office and put it on the secondary line. I also love the sound of its mechanical ringer when calls come in, and the comments I get when people see it there.
They're amazed when I tell them that yes, it works, and yes you can still dial with it on today's phone system.
Unfortunately, when the analog line it's on is replaced by a VG248 "fake analog" line, which is really VoIP with an adapter, the rotary dial pulses will no longer work. {:(
An era of backwards compatibility is slowly ending. Pulse dialing will slowly stop working on analog phone lines over the next few years or so...
-Z
my parents didn't have a push button phone till about 3 years ago. And they still have 3 rotary phones in use in the house. We finally bought them a cordless phone, so they made big leap. They simply didn't want a new phone, like many people, if it's not broke why waste money on it. They make more then enough money, but they just bought a "new" car a year ago, it was a 97, my father drives a 92.
Until we bought them a new tv 2 years ago they still had their tv from 1984, bought after the previous one broke. Then we had to get them a VCR, they were on their second one since 84, and it's used 5 nights a week to record the news to watch later that night. Also they didn't get cable tv till 1999.
Plenty of people stick with what they have, this is why no new tech will ever sweep through and eliminate something old. The old base has momentum and lots of it. On a more related to slashdot perspective, their computer is a PII 400 that was still running the original install of win95 that came with it up until about 1.5 years ago when we put winXP on it (note that for being an install of win95 that went for years it had no virus or Trojan issues and such). It just worked for them, and they don't want a new computer anytime soon.
First post via rotary phone! Took me a while to dial my ISP, but I hope I still got the first comment.
1. Rotary phones were built to last (unlike many digital phones). They can survive a drop from a two story building onto concrete. Just go down, pick it up, plug it in, and it will work.
;-) )
:-)
2. Rotary phones can withstand 300lbs of pressure before they will break or deform.
3.Rotary phones can withstand temperatures of up to 1,000 degrees. This may seem a stretch, but rotary phones have been in buildings which have burnt to the ground and still worked.
4. You do not need to be able to dial a rotary or digital phone. You just need to be able to push the button/hanger on the phone. As the original poster stated, the way in which rotary phones work (not cell phones mind you) is that they disconnect for a short period of time (like a 1/10 of a second) and then reconnect. What you might NOT know is that all digital land lines can be operated as a rotary phone too. So in an emergency, all you need to do is to tap the button/hanger on your phone's base with a slight pause between the dialing of the numbers. It will still connect. (So to call 1-411 would be one click, a slight pause, four clicks, pause, one click, pause, and one click. Try it sometime.) (I used to do this to dial out from the university on phones with a phone lock on them!
5. Digital phones sometimes have a switch on them to switch between rotary mode and digital mode. You can switch it to rotary mode, dial the number (and hear the antiquated clicks), and then switch back to digital mode to handle any of those "Press 1 to do Blah". I discovered this at my mom's house. She had rotary service (way out in the country!) but I'd dial the line, let the roatry part go through and then switch the phone over to digital mode to do things.
6. Digital phones can be dialed by whistling into them. It isn't easy but you can do it if you practice long enough (and are bored enough).
7. One of the last interesting things to know is that if you are ever, ever stranded somewhere with a broken phone and you need help, you can still use the phone line and dial the phone. All you need is to bare some of the wire and you have a telegraph. Hold the two wires together to complete the circuit and then use the two wires just like you would the button/hanger. Take them apart and you break the connection. Hold them together and you've got a connection. Operators are probably not as smart as they used to be about this (since telegraphs are not so common place anymore) but it used to be that you could do the old SOS and they would send someone. However, if you dial 911 using the above method and twist the two wires together afterwards the police will come out to investigate.
Just a bit of FYI stuff.
Someone put a black hole in my pocket and now I'm broke.
I have both used an abacus and washed my clothes on a washboard. But I don't feel superior for being older. Instead, I feel ... er, older. Look at all this gray hair! Well, the women like it, so it can't be all bad...
I honestly think that they should teach at least college math students how to use an abacus and a slide rule. The reason is simple--- if you are really trying to learn *math* instead of *arythmatic,* these tools really help you get the feel of how the numbers actually work.
BTW, I am in the under 30 crowd.
I teach people how to use computers. And I *start* by going back to basic concepts. I start by explaining the really technical concepts in plain English like they did in the user manuals from the late 1980's. That way people have a fundamental sense of how things fit together and the computer is not so scary.
Altogether too many things classified as "progress" are actually simply things which make us disconnected from the fundamentals of how things actually work.I do still find important uses for old technology. In particular the old telephones do a great job of explaining the various problems and solutions for two-wire voice traffic and are a whole lot more accessible intellectually than the newer ones.
LedgerSMB: Open source Accounting/ERP
Motorola makes something called a "Cellular Connection". It's a box that plugs into the phone on one side, and provides an RJ-11 POTS (Plain Old Telephone Service) connection on the other. It supports pulse dialing too so there's no need for any PIC firmware debugging.
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Sigs are a waste of space
that "whis-k-k-k-k-k-k-k-k-k-whis-k-whis-k" is the rotary equivalent of 911? Am I the only one who got it? Just a thought.
I find this to be an interesting comment, because non-rotary phones are *NOT* digital. They (well, in North America) are DTMF, meaning they work with two tones played at once to signal the button press. This is all calculated by having one frequency for each row, and another for each column. When you press a button, the row and column tones are played, making the indicated dual tone. As such, you cannot dial a DTMF phone by whistling, unless you are capable of whistling two notes at the same time.
One other interesting bit of trivia is that DTMF phones can have a fourth column of buttons A, B, C, and D. However, these typically would only be found on test sets and AUTOVON (US Military) phone systems.