Slashdot Mirror
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.
I'm 19, and I used a rotary phone for probably ten years growing up. I'm sure a lot of Slashdotters have if they moved into an older home. The only real drawback to the phones is that there is no way to punch in numbers after connecting. When you hear "Press 1 to ...", the phones cannot handle doing that.
I have fond memories of rotary phones, though. The satisfying click click click, the durable construction; they come from a time before phones were $10 pieces of junk. It's the same reason why so many programmers like the IBM Model-M keyboards.
Systemd: the PulseAudio of init systems
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.
.
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.
On a regular US land line, the incoming signal that sets the phone ringing is 90 Volts peak-to-peak. This voltage more or less drives the coils on the ringer directly. Because it's a genuine electromagnetic affair, it sucks down tons of current -- far more than you're going to get out of a puny cell phone battery running through an inverter.
You're probably better off just playing a sound sample of an old-style ringer.
Schwab
Editor, A1-AAA AmeriCaptions
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
No-one actually has these anymore. But most people have used them. The rotaries were replaced by keypads and even wireless in-home-proprietary systems in the 90's... anyone older than 20 must have used them. I remember using the rotary throughout the 80's. It's not like this is ancient history. And FYI, the 8-track players... in Finland I have _never_ seen even one. I'm 31. It was all C-cassette and radio, and shitty small japanese Datsuns for the mainstream. The 8-track must be an American-only-thing? I do have A-TRAC by Sony... PS. (the Datsuns were a hit in Finland in late 70's because the japanese pioneered targeting a car for a specific climate and audience.)
'Once scientists, even the dim-witted social scientists, get muzzled, the Western Civilization is finished.' - oldhack
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.
Oddly, they used to make drop-in replacements for those carbon buttons that were more modern, but it's probably getting harder to find them than the genuine thing.
Also, the user interface issue of not knowing whether there was a problem with the call makes the hack much less cool, since much more annoying. Even if it ruined the retro feel some indication should have been given of call status. An unobtrusive LED near the base of the phone would do. For that matter some old office phones had a "message waiting" light that was incandescent, but you wouldn't notice the difference if you dropped a white LED under the dome. That could have flashed a few status messages to let you know why things weren't working as they are supposed to.
Brackets contain world's first nanosig, highly magnified:[.]
For quite a while now I have wanted to take an old handset like the ones on a rotary phone and make it into a bluetooth handset for my cell phone...
Kinda like a wireless Pokia
moo.
First post via rotary phone! Took me a while to dial my ISP, but I hope I still got the first comment.
Back in 1985, there used to be a device made by a company called Tellular that replaced the handset on the brick-phones of the day. That had a dial tone and loop current generator, and sensor for off-hook, (and of course dial pulses, which are rapid hookswitch pulses), and DTMF's. The device would also generate a 100V ring pulse for incoming calls. The net effect was you could plug a standard rotary or DTMF house phone into the box and it would fake a network interface, dial the cell phone and hit send automatically.
I co-designed a system called "Limo-Phone" that interfaced between the phone and the Tellular box to time and charge for the call. This would let a Limousine have a standard TrimLine or Princess phone in the back, the fare could place calls while there like a normal phone, and the device would tally up the bill at the end of the ride!
-- You are in a maze of little, twisty passages, all different... --
As soon as the AT&T breakup happened, lots of cheap touch tone phones flooded the market and people upgraded.
Or downgraded. I'd say the peak of landline technology was the touchtone version of the phone in the article. Compared to those, most phones since have just been cheap crap. Cheap crap with lots more features, granted, but show me anything since that equals the reliability, that has as well-designed a handset.
When they just rented the phone to you, and if it didn't work they'd have to send a guy in a truck to your house, they built 'em to last.
Every modern phone I've seen has a little Pulse/Tone switch on it somewhere, usually in the back. (Even portable phones.. not, obviously, cell phones, since they use neither method to send the number.) I always thought this was a curious artifact of an era long gone, but if you really wanted to stick the phone company for $1.50 a month, I suppose you could switch all your phones to 'pulse' and cancel the touch-tone service.
~ Aero
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 remember being a trepedacious teen trying to work up the courage to call a certain girl... and sitting there with my finger against the stop, the last number (a nine) half-dialled, heart pounding.
:D
I haven't thought about that in years. I guess now you could say it was "Obsolete Panic."
I have an old rotary dal that I converted into a controller for my old Atari 800. I managed to find some black plastic RS232 connectors, some RS232 cable, black duct tape, and the rotary handset. After soldering four lines of the RS232 cable onto the handset, I played around with a voltmeter to figure out which connections were being closed and broken as the dial rotated (interesting to note that 0 generates 10 pulses). These were then wired up to generate a TRIG() press whenever the dial rotated. Fortunately, the rotation of the dial was so slow, even a simple Basic program could determine which number the user has selected.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
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.
--
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.
Regarding your #7--Does this mean if you just tap your receiver hook in an SOS pattern, you might get a visit from your phone company?
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.
The line to our house simply couldn't do touch tone. I don't know why. (I was just a kid!) But we had to have our line 'upgraded' to support it.
I think this was relatively common. Not sure what the technical reason for it was; I should ask my dad, he was a phone company engineer back when there was only one phone company. (Actually there was never really only one.. but you know what I mean)
Remember the phones that had buttons, but still clicked like a rotary? Those were for folks who wanted buttons but who didn't or couldn't upgrade their lines.
I also recall standalone touch-tone generators. Just a touchpad on remote-control-sized box with a speaker that you could hold up the the microphone of a rotary phone and dial the number. I honestly don't know if these were actual consumer devices or some sort of technician's/phreak's tool.
where there's fish, there's cats
One of my college professors told this story in class 5-6 years ago...
He had a rotary dial phone, and refused to pay for touch tone service. At one point, the phone company (BellSouth) started calling and trying to sell him touch tone service for ~$1.50 a month, but he refused. He didn't need it. Why should he pay for it?
As it turns out, he was apparently the only person in that area that did not have touch-tone service. BellSouth told him that maintaining the old equipment to support his line was costing them money. So, since he refused to pay for the service, they gave it to him for free.
(I don't work for the phone company, so I don't vouch for the story's technical accuracy.)
It doesn't hurt to be nice.
It's down in my basement. It came with the house, actually. Since every other phone in the house requires A/C to function, it's useful to have around for power outages and such.
TouchTone is NOT digital -- it's an analog dialing system, in fact, the only analog telephone dialing system of which I can think.
Actually, there are three ways to dial digitally with plain old landline telephone service:
*The pulse switch that most phones have
*Tapping very quickly
And you guessed it, since pulse dialing is digital,
*A rotary dial.
Which shows you that progress isn't always digital -- the whole advantage of TouchTone is that it uses sounds within the spectrum of the human voice, meaning that the circuits need no capacity beyond what they already need to pass along DTMF -- which facilitates the menus. This is why cell phones go into a TouchTone mode after the call has been placed by their internal digital dialing systems which are nothing like TouchTone or pulse.
I once read that today's phone system is still electrically compatible even with phones that predated dialers. If so, you could connect one of those old wooden phones from the 19th century with the separate microphone and earpiece. If you are skilled enough with rapidly toggling the hook, you could even dial numbers (you can try dialing that way on touch-tone phones too).
From 1978-1982 I worked in a Central Office in south Georgia that only supported Rotary (pulse) dial telephones (we even had "party" lines back then.) The reason was, the entire phone switching system was electro-mechanical. When you rotated and released the dial on your black or beige Stromberg-Carlson model 500 phone, an entire set of X-Y stepper switches, housed in a building the size of a small gymnasium, mechanically moved to complete the connection. The noise was unbelievable, >90dB at all times, and I have hearing loss to this day from my four years of working in that concrete building. When a backhoe operator cut a large cable somewhere, we immediately knew when there was about to be a lot of trouble tickets, because the sound of many banks of switches slamming shut simultaneously could not be ignored. I still love the old, heavy, tough rotary phones, because they are, in fact, a representation of the old, heavy, tough switch buildings that very few people have ever seen in action. For the most part, they're gone now, but once upon a time in technology, they worked extremely well. I'm fascinated by this retro curiosity in rotary dial handsets.
I see your whistiling DTMF and raise you speaking 75 baud!
He stuck it to the man big time. They gave him his phone call at the police station, but he gave them a bogus number. They put a metal plate over the keypad so he couldn't hack them.... OR SO THEY THOUGHT: He hung up and dialed his hacker buddy with the reciever. What a HACKER!
I believe this character was modeled after Kevin Mitnick, who could negotiate modem connections and send data (ie. hack your planet) using only his mouth and a phone.
I distinctly remember seeing a rotory phone hooked up to an acoustic coupler in the movie. It had an automatic mechanical thingie that worked the rotory dial. Morpheus used it to hack into the Matrix!
The line to your house was probably fine - it was probably the telephone exchange equipment at the other end that didn't do touch tone. The odd Strowger exchange was still hanging on as late as the mid-90s as well as the odd Crossbar. Electromechanical switches just couldn't do it.
In Britain, there was a different problem - in the 1980s, many exchanges were electronic, but they couldn't do touch tone because of the frequency of the dialing tone (a 50hz purring sound at the time). It would have been easy enough to change the dialtone to the one we are familiar with today, but bureacratic inertia stopped it (We still have Strowgers and Crossbars - the dialtone must be the same over the whole country was the argument used). This eventually gave way when System X and System Y digital exchanges started to appear in the late 80s. System X and Y are still in use today.
After my grandmother died, I kept her 30 year old rotary dial telephone as something to remember my grandparents by. I obtained an original wall junction box for it and wired the RJ-45 plug to that instead of modifying the phone cord, so the phone is completely original. Still works like new.
Go to http://www.light-straw.co.uk/ for some excellent historic information on the British phone network. One of my favorite bits is the story from the international operator at Faraday House from the 1970s.
Oolite: Elite-like game. For Mac, Linux and Windows
DTMF numbers are made of two separate, simultaneous tones. For instance, the number one is a combination of 1209Hz and 697Hz. Please enlighten as to how you can whistle two tones at once.
You forgot:
8. Rotary phones are the only way out of the matrix.
I have no idea how to make soap though.
This one I know (thanks to my chemistry teacher of long, long ago)
Animal fat and or oil, rainwater, ash and salt
Ash + hot soft water -> lye water
(you can use caustic soda instead, and generally do, but if we're talking survivalist I guess the assumption is that it's unavailable)
Note: lye water burns, so don't put it in anything that'll dissolve, drink it, bathe in it, etc.
Shove melted animal fat in water and remove the nasty floaty bits, add salt. You can de-stink the fat using sour milk.
Now: mix lye water and grease, boil out excess water, add salt, set it and let it dry.
Note: if you get the wrong quantities of lye water, the result will burn.
I recall we did this in class using caustic soda and synthetics, but our spoilsport of a teacher wouldn't let us try the resulting liquid goo on our hands. I have a hole in one arm of my lab coat from unofficial testing of the stuff (which looked like The Blob) so he may have had a point.