For example, if the user dials "6" on a North American phone, electrical contacts wired through the cam mechanism inside the phone will open and close six times as the dial returns to home position, thus sending six pulses to the central office.
Western Electric experimented as early as with methods of using mechanically activated reeds to produce two tones for each of the ten digits and by the late s such technology was field-tested. But the technology proved unreliable and it was not until long after the invention of the transistor when push-button technology matured Over the next few decades Touch-Tone service replaced traditional pulse dialing technology and it eventually became a world-wide standard for telecommunication signaling.
The most important factor is that at the time that telephones were invented, there was no such thing as automated call routing. There were people sitting in central switching stations. You told them, "Connect me to Mrs. Johnson", and they replugged the wires -- and here you go, you're now connected to Mrs Johnson. Later, automated call routing was invented, but it did not use tone dialing yet — that would have been too complicated for the simple electronics to handle, because the switching system mainly relied on relays.
Instead, it used pulse dialing , which is much simpler. It can even be mechanical read about rotary selectors. Consider that the difference between pulse and tone dialing doesn't only exist on the end-user side, or relate solely to the user experience.
You must also take into account a variety of other factors:. Back then, telegraphs were in common use. Mostly, these worked mechanically. Later versions were upgraded with electronics, but that's of lesser importance.
To achieve automated call routing based on pulse dialing , you could use mechanical and later, electronic parts that were similar to those already being used in telegraphy. These made for lower cost, quicker introduction into public service and easier maintenance. Tone dialing , on the other hand, requires relatively good filters and detectors to match the tone frequencies.
It is also more difficult to generate tones than pulses. As the electronics improved and tone dialing started to be feasible, its introduction followed, since tone dialing is generally less prone to noise and errors than merely "counting clicks". There was no such thing as "press that to start a process which does A, B and then C". And of course, there were "sliders": knobs and sliders. In other words, all the traditional potentiometers and suchlike.
Currently, we are all familiar with the notion that if you press a certain button, a machine will start, and that if you press that same button 5 times, the machine will perform its action with 5 levels of increasing intensity. That's easy. But doing this requires a complex circuit which counts the presses, plus a DAC that converts the count to a particular voltage or capacitance etc. They were simple mechanical devices. For pulse dialing, where you need to emit more or less pulses, a rotary or sliding device is the first thing that comes to mind.
Let's suppose you need to emit a given number of pulses. So we'll take a tube full of N contacts and a metal ball: if you drop the ball into the tube, it will "connect" exactly N times. Take 10 tubes, each with a different number of contacts, and you can very easily emit 1 - 10 pulses just by dropping a ball through the right tube.
It's easy. It's cheap. It works. Maintenance is trivial. There are no complex or expensive circuits. But it's also harder for the end user to use.
A rotary device with an automatic spring-loaded return would be so much better, and almost as cheap! Of course, this account is merely my surmise: I don't know what the exact reasoning was at Bell Labs etc. I have simply made an educated guess based on my own knowledge of the technology.
After watching the video, I have some doubts about the veracity of their reactions, at least for some of them, but leaving that aside, I think the main problem now is that button interfaces are very common, almost anything is now a button, so the first reaction is to press something. Phones, remote controls, interfaces on computers and tablets, microwaves, washing machines although some still have a dial for adjusting settings selected with a button , etc.
Before this modern times, we had many different interfaces, the rotary phone, hard to press buttons or dials on blenders, dials on washing machines, little lever like controls on electrical devices, watches, etc. So we where more used to variety and rotary elements.
The rotary system is a mechanical mechanism that was available way before electronics where around and it was easy to implement with the desired precision. I could explain how that work, but the next quote from the Rotary dial article on Wikipedia summarizes it very clearly.
On the rotary dial, the digits are arranged in a circular layout so that a finger wheel may be rotated with one finger from the position of each digit to a fixed stop position, implemented by the finger stop, which is a mechanical barrier to prevent further rotation.
When released at the finger stop, the wheel returns to its home position by spring action at a speed regulated by a governor device. During this return rotation, the dial interrupts the direct electrical current of the telephone line local loop a specific number of times for each digit and thereby generates electrical pulses which the telephone exchange decodes into each dialed digit.
Each of the ten digits are encoded in sequences of up to ten pulses. For this reason, the method is sometimes called decadic dialling.
The reason was that the telephone system required pulses to represent the numbers, and the technology did not exist at the time to generate pulses from pushbutton presses in a simple consumer device such as a telephone. The first automated telephone exchanges used electromechanical Strowger stepping switches that advanced one position for each pulse received.
The pulses from the electromechanical dial on the phone could directly control the stepping switches in the CO to connect the "in" line to the "out" line. That was replaced gradually by electronic "touch tone" DTMF signalling, but the electronic exchanges of today still generally support pulse dialing. As recently as the s I saw an operational electromechanical phone exchange in Blagoevgrad, Bulgaria they had colorful lights wired to the steppers so it created a kinetic art effect behind the full-length windows in the central office.
I don't have evidence for this, but I think it is an example of end-end system design between the selectors in the exchange, the handset and the user. To route through one selector you need to connect and disconnect the battery a specific number of times, giving time between each 'pulse' for the selector to move into position.
So you need something that works like a music box or pianola to pace the pulses. A spring winding down against a brake was the obvious way to do this. Winding the spring with the clockwise motion and letting it unwind with the release provided motive power.
Note that we don't have any UX, here, what we have is the user as a vital mechanical part of the system. Now the UX comes in with the design of the dial so that one inserts ones finger in a numbered hole and always moves all the way to the end stop.
There is a little 'ting' when the dial reaches the rest point so one knows one can start dialling the next digit. When I was a child, 4 digits was the most we ever had to dial. Our number was To dial anyone else on the exchange was 4 digits and any other call was to dial the operator. I can't remember when we got Subscriber Trunk Dialling, probably around It is a really lovely piece of integrated design, self-powered, usable in darkness, or by blind people, and immensely robust.
Replicating all it's features with a touch tone system required many non-integrated features like bumps to find the home key. Before the rotary dial, a calling design existed that was far more complicated to use and therefore, it was not appealing to the everyday user.
These phones did use push-button technology, however, they only had three buttons. The three buttons were measured as s, 10s, and single units. For instance, if someone were to try calling the number , they would first need to press the s button, followed by pressing the 10s button eight times and the single units button twice.
Now people may think that waiting for a rotary dial to spin back multiple times just to dial a number may be an annoyance, but based on past findings it seems to be infinitely easier to dial using three rotations rather than 11 pushes. The telephone itself is able to make phones calls by converting sounds the voice into a powerful electronic signal that travels through a network of cables , a telephone network, to various other telephones.
Telephones contain a microphone that the user would speak into and on the opposite end, the earphone would receive the sound from another location.
The rotary dial was designed as a circular layout that allows the user to insert their finger into a hole that corresponds to different digits of Some models also include letters that correspond to each number. Once the finger is inserted in the correct location the user would rotate the desired number all the way around the circle until they heard a soft clicking noise. Related: Check out some of the best vintage phones you can find today…. To use a rotary phone , simply pick up the phone receiver and insert your finger into the number holes.
After you have made your call, set the receiver back on the phone to end it. However, some telecom providers might not deliver service to this unique type of phone because it sends pulses to a number, not strong electrical signals. Rotary phones stopped their mass production during the s when newer and more advanced phone models were entering the market.
As one of the original rotary phones, the Candlestick Model 50AL made headlines in for being the first free-standing rotary phone. This product has a long candlestick-like neck that has a number dial on the bottom and a large mouthpiece on the top.
Attached to the side is a handset that connects to the receiver with a long wire. Created in , Model was a step up from the Candlestick. Instead of having an extended neck, it features a round base with a receiver placed on top of it horizontally.
This was first introduced in the early s and the World's Fair under the trade name "Touch-Tone. If you have an old rotary dial phone lying around the house or fancy adding a touch of retro-tech to your home, you might have wondered if it might actually work today?
The answer might actually surprise you, though it does depend on your service provider. One Verizon Wireless worker does offer a quick way to check if it's a viable option. If this works, you have proven that a rotary phone will work.
Great news. Rotary phones also have some benefits over their more modern counterparts. It seems that they would prove invaluable during a power cut. According to another Quora user, Talmort O'Dole , these old phones should still work. But of course, as with any advice, you should always contact your service provider to check before purchasing one. Unless you are not bothered about whether it will work or not of course - they are quite attractive ornaments after all.
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