We're in NA so it was a huge mystery as to why this was happening just with their extension, took a while before we realized what was going on.
So think of the cradle switches - what "hangs up" the phone - as a button, and you just click that button (quickly) for '1' and then you pause and hit it twice in very rapid succession for '2' ...
You need to be on a POTS line to do this, of course, but it will work even today. Even if you have no dialing mechanism, you can dial the phone this way ...
This brings back memories, this is a trick people my age group mastered as teenagers in a 3rd world country. All calls were billed - including local ones, so parents would commonly get lockable cages that would cover the buttons/rotary dial to prevent unauthorised calls in their absence. The cages would leave the receiver accessible even when locked in order to be able to receive calls, so we would use the hook to do pulse tone dialing; dialing a number with many zeroes was always a challenge since it required 10 rapid taps as part of a longer sequence, but I built up muscle memory.
The practice was colloquially named 'tap-dialing' and it was handed down from generation to generation. Sadly it came to an end in the smartphone world.
”The voltage at the subscribers end depends upon loop length and number of ringers attached to the line; it could be between 40 and 150 Volts.”
I think they also (relatively to the hardware in a VoIP adapter) need a large amount of power.
So, to ring that bell, you need to transform your 5V/3V/…, and you need a larger power circuit. That isn’t worth it for the few who still have an old-style telephone.
To dial a 0, pulse the line 10 times.
1 + 1 = 2
Actually, I’ve heard that on cell phones in EU, you can still dial 911, and it’ll connect. I have had occasions to call 112 before, but it’s always been in big enough emergencies that I didn’t have time to experiment. I’m eagerly awaiting the day when I come across an emergency that’s urgent enough to call 112, but not urgent enough that it can’t wait a little bit for me to try something. It’s a delicate balance
That's why the UK went with 999 as something memorable, but slow to dial.
The reverse dial was a result of the design of early Rotary exchanges built in Antwerp around 1921. Similar Rotary exchanges were installed in Oslo as well in 1914, and Oslo also used the reverse dial (but nowhere else in Norway).
Sorry. Someone had to.
In Europe many of them are variations of 1XX, but since there are so many and sometimes they change too, it's not trivial to remember which one.
The American 911 is more memorable, even in Europe, simply due to it appearing in popular culture so often, I hope that if someone dials that one in Europe it'll also get forwarded to a real emergency line.
Eh? 112 works in the whole EU. As your link says. Of course old legacy numbers also work in many countries.
Just like the US, every country in has its own emergency numbers that you should probably know if you're in that country, but for Europe as a whole, 112 is the universal emergency number.
And while 911 might be known to many outside the US, as a number that requires actually navigating the dialing pad, it's not all that great. The UK's 999 or Europe's 112 are far better at being something you can dial while under duress (with 999, as a repeated number, being by far the superior choice here).
I bet little kids would constantly pick up a phone and dial “999999999”.... harder to mistakenly / playfully dial “911”
>Up until 1968, the United States was still using hundreds of seven-digit emergency telephone numbers across the country. In fact, some states, like Nebraska, had more than 180 different ambulance service numbers alone.
>The code 911 was chosen because it best fit the needs of all parties involved,” according to the National Emergency Number Association (NENA). “First, and most important, it met public requirements because it is brief, easily remembered, and can be dialed quickly. Second, because it is a unique number, never having been authorized as an office code, area code or service code, it best met the long range numbering plans and switching configurations of the telephone industry.”
I can't find the sound fx library online anymore but it had all sorts of sound effects used in TV and movies from the 50s to today. I've heard the effects in Looney Toons cartoons, classic Scooby Doo, Mission Impossible, and Knight Rider just to name a few.
Unfortunately I didn't think to keep the entire library and so I only have a few sound files from it converted to MP3.
But these days everyone just keeps their phone on silent anyway...
You used to be able to buy them too: https://www.sparkfun.com/products/retired/286
It seems like for hobby projects it's really hard to get good battery run times. I wonder why that is. Is is difficult to get everything into the appropriate sleep modes, or are hobbyist parts just that much more power hungry?
Commercial feature phones have stand by times measured in weeks.
The module appears to be https://simcom.ee/modules/wcdma-hspa/sim5320/ hardware data at https://simcom.ee/documents/SIM5320/SIM5320_Hardware_Design_...
... which claims a standby current of about 2.5ma. So either it's not correctly entering standby, or most of the power is going somewhere else. If the LED bargraph runs continuously that would explain it, but I assume she's thought of that and it's triggered by a button. Or doesn't mind the 24 hour battery life.
Having said that, hitting "more than a day of usage" is crucial, anything more than that is much less important for most users.
In other cases, the boards aim to be small instead of complete, so just use a simple LDO to power the device from USB. This uses a ton of power even if the MCU is off, and that's where the battery drain goes. Designs for real products tend to use a DC-DC converter that can be tuned for the desired sleep state.
Finally, the software that hobbyists use is basically designed to be easy, not efficient. You don't write any MCU init code, it just turns all power-sucking peripherals on by default. That way when you go to use them, they work! Accessing MCU-specific features to save power tends to be difficult, because the hobbyist stuff is designed to support every MCU ever designed from decades-old AVR chips to the latest ARM cores. If you're willing to include a bunch of headers and hack around what they do for you, you likely break core things like "read a GPIO pin" or delay_ms(). All in all, it seems unlikely to me that anyone is going to buy an Adafruit board, program it with Arduino, and get a low power device. I tried and failed. Adafruit themselves recommend using an external device to turn the board on and off at a scheduled interval to save power.
(I made an interesting nRF52 clock / temperature sensor with an e-ink display a few months ago. Every minute, the RTC interrupts the MCU to wake up, refresh the display, and send the temperature/humidity data out over BLE. I used Arduino and ... never got the power usage down at all. It lasted for A DAY with a 100mAh Li-ion battery, even with the radio disabled completely. The voltage regulator just burns power while the MCU is asleep waiting for that minute interrupt. As it happens, it is super jarring when the e-ink display refreshes itself every minute, so I ultimately abandoned the product.
Also somewhere in there I realized that using Arduino is a giant waste of time. When you just write your own C code, all of the manufacturer's documentation suddenly becomes applicable, you can use fancy things like an RTOS, and you even get code completion with clangd in your editor. Every time someone mentions microcontrollers I get mad at myself for wasting so many years with hobbyist-grade tools that never worked right. But I digress.)
An interesting exercise is comparing the nRF52 reference design (deep inside a ZIP file from here, https://www.nordicsemi.com/Software-and-Tools/Development-Ki...) with something like Adafruit's nRF52 dev board: https://cdn-learn.adafruit.com/assets/assets/000/052/793/ori... You will notice that Nordic's dev kit has a very complicated power stage, with solder bridges to turn off creature comforts for better power efficiency. Adafruit just has a random linear regulator on there.
Demon Dialer 176T (the high-end model that stores 176 numbers!)
>In the computer hacking scene of the 1980s, demon dialing was a technique by which a computer was used to repeatedly dial a number (usually to a crowded modem pool) in an attempt to gain access immediately after another user had hung up. The expansion of accessible internet service provider connectivity since that time has rendered the practice more or less obsolete.
>A similar technique was sometimes used to get the first call for prizes in radio "call-in" shows, thus leading to the adoption of random "fifth caller," "seventeenth caller" etc. by radio stations to circumvent this practice.
>The term "demon dialing" derives from the Demon Dialer product from Zoom Telephonics, Inc., a telephone device produced in the 1980s which repeatedly dialed busy telephone numbers under control of an extension phone.
>"Demon dialing" was popularized by the movie WarGames, which demonstrates the hacking technique (the technique eventually evolves into a technique called "phreaking"). After giving the program an area code and 3 digit prefix, the program then serially dialed every phone number in that prefix in order, recording which phone numbers were answered by a computer modem. Soon after, most likely because it was popularized by the movie, serial dialing was outlawed. Hackers got around this by simply randomizing the order the program dialed all the numbers. Later the terms "demon dialing" and "war dialing" became synonymous.
Why "more practical"? How is a desk phone more practical than a portable one?
For outbound calls if you encounter an IVR menu (press 1 for english, etc), the ATA will translate pulse dialing into DTMF tones. Functionality I think this example is lacking.
i concur with the whole functional simplicity thing.
But I think the dial is anachronistic, despite what's claimed; A bit like fitting your car with reigns for steering and a whip for acceleration.
The only 'functional' aspect of it is perhaps that it slows down your dialing enough (especially when your finger slips on a number, and you have to start over!), for you to think whether you really need to make that call.
And I agree it's fun and a cool project, regardless of utility
I'll see myself out.
I just spent far too much time pondering the feasibility of a reign / whip controlled car. The trickiest part might be designing the filter to detect the crack of a whip reliably. Also wondering if there are any laws regarding the form and location of steering and acceleration mechanisms.
* Real, removable antenna with an SMA connector. Receptions is excellent, and if I really want to I could always attach a directional antenna.
* When I want a phone I don't have to navigate through menus to get to the phone "application". That's bullshit.
* If I want to call my husband, I can do so by pressing a single dedicated physical key which is dediated to him. No menus. The point isn't to use the rotary dial every single time I want to make a call, which would get tiresome for daily use. The people I call most often are stored, and if I have to dial a new number, or do something like set the volume, then I can use the fun and satisfying-to-use rotary dial.
* Nearlt instantaneous, high resolution of signal strength and battery level. No signal metering lag, and my LED bargraph gives 10 increments of resolution instead of just 4.
* The ePaper display is bistatic, meaning it doesn't take any energy to display a fixed message.
* When I want to change something about the phones behavior, I just do it.
* The power switch is an actual slide switch. No holding down a stupid button to make it turn off and not being sure it really is turning off or what.
Finally there was one long distance service that used speech recognition to dial numbers! It would repeat groups of 3 or 4 digits you spoke, and ask you to verify they were correct with yes or no. If you said no, it would speak each digit back and ask you to verify it: Was the first number 7? ...
The most satisfying way I ever made a free phone call was at the expense of Bell Communications Research (who were up to their ears swimming in as much free phone service as they possibly could give away, so it didn't hurt anyone -- and it was actually with their explicitly spoken consent), and was due to in-band signaling of billing authorization:
Peter Langston (working at Bellcore) created and wrote a classic 1985 Usenix paper about "Eedie & Eddie", whose phone number still rings a bell (in my head at least, since I called it so often):
>(201) 644-2332 or Eedie & Eddie on the Wire: An Experiment in Music Generation. Peter S Langston. Bell communications Research, Morristown, New Jersey.
>ABSTRACT: At Bell Communications Research a set of programs running on loosely coupled Unix systems equipped with unusual peripherals forms a setting in which ideas about music may be "aired". This paper describes the hardware and software components of a short automated music concert that is available through the public switched telephone network. Three methods of algorithmic music generation are described.
Eedie & Eddie (And The Reggaebots) - Some Velvet Morning (Peter Langston)
>At the time I was also running a telephone demo that you could call up to hear samples of music composed for you while-u-wait by the computers in my lab. Most people called the mono telephone number that gave you a monophonic mix of the stereo channels, but you could also call either the left or right channel, or both, one phone on each ear, to get stereo -- this was how I worked from home. The elaborate phone connections were from the telephone switch in Brian Redman's lab.
>When the call would come in, the computers in my lab would start composing the 6 or 7 pieces that were played in the demo, while a voice synthesizer in Brian's lab (Eedie) would accept the call (we paid the long distance on a few collect calls from music researchers in other parts of the world) and introduce the demo, explaining what was going to happen, then the call would be switched over to my lab where another voice synthesizer (Eddie) would take over, introducing each piece as it was played.
>The idea for Eddie's voice came from the overly-happy shipboard computer in the Hitchhiker's Guide to the Galaxy radio serial. In the phone demo Eddie would say something like:
>Hi! This is Eddie! Your computer music phone, FRIEND!
>Oh BOY! You are rilly rilly going to like this music, I can TELL!
>First, I'll just make sure that Peter's computer is working, and then we can share-and-ENJOY!
>This is pretty much the kind of thing that Douglas Adams' computer said, and he was named Eddie, so we used Eddie as an homage. Then, when we wanted the voice-synth that answers the phone in Brian's lab to be female, we considered how, later in the Hitchhiker's Guide, Zaphod Beeblebrox chooses a different personality module for the computer and gets a worried old lady's voice -- "This will all end in tears!" but Adams never gives her a name, so I chose "Edie" as a feminized "Eddie". Unfortunately, the DECtalk voice synthesizer we were using pronounced E-d-i-e just like E-d-d-i-e with a short E vowel "eh" at the start, so we had to spell her name E-e-d-i-e in order to get the long E initial vowel sound.
>Anyway, the little chit-chat between Eedie and Eddie at the beginning of the recording of Some Velvet Morning is typical of the sillier moments in the phone demo introductions, and is included as an attempt to familiarize the listener with their strange accents.
When you called (201) 644-2332, the Dectalk speech synthesizer would answer, say "Hi! This is Eddie! Your computer music phone, FRIEND!", wait a few seconds, then cheerfully and sincerely announce, "Yes, operator. I will accept the charges."
LGR Oddware: $1,200 DECtalk PC Speech Synthesizer
Then Eddie would launch into his greeting and introduction to the phone tree of cool demos, like singing songs, telling jokes, generating improvisational music with L-systems or Stochastic Binary Subdivision, playing games, reading news summaries and weather reports, etc.
But then some "music researcher in other parts of the world" realized that it was perfect for making operator assisted third party collect phone calls!
Did you ever trick the phone company into cheerfully accepting the charges of a third party phone call? You will!
>A third number call or third party call is an operator assisted telephone call that can be billed to the party other than the calling and called party. The operator calls the third number for the party to accept the charges before the call can proceed.
So you could just dial 0, tell the human operator that you want to call any number you wanted, and charge it to (201) 644-2332. Then they would call that Morristown, New Jersey number for authorization, Eddie would answer, the human would ask "Will you accept the charges for a collect call from ... to ...?", Eddie would then cheerfully announce, "Yes, operator, I will accept the charges!", and the human would say "thank you" and hang up on the loosely coupled network of Unix systems with unusual peripherals at Bell Labs, then connect you through for free to whoever in the world you wanted to talk with, for however long you want to talk, charging the call to Bellcore!
"Share and enjoy!"
Also, isn't it easier to have a second landline phone attached vs having to play DTMF tones from a phone app?
It was a very fun project and I learned a lot about electronics doing it!
Speaking of "old school", I love watching Joan Rivers shamelessly plug MCI, after which she audaciously asks Ernestine how old she is and grills her about her sexuality:
> In 1970, AT&T offered Tomlin $500,000 to play her character Ernestine in a commercial, but she declined, saying it would compromise her artistic integrity. In 1976, she appeared on Saturday Night Live as Ernestine in a Ma Bell advertisement parody in which she proclaimed, "We don't care, we don't have to...we're the phone company." The character later made a guest appearance at The Superhighway Summit at UCLA on January 11, 1994, interrupting a speech being given on the information superhighway by then-Vice President Al Gore. She appeared as three of her minor characters in a 1998 ad campaign for Fidelity Investments that did not include Ernestine or Edith Ann. In 2003, she made two commercials as an "updated" Ernestine for WebEx.
phone company sketch - we dont care - Tomlin
Ernestine's House Call - Saturday Night Live
Ernestine the telephone operator calls General Motors
Lily Tomlin as Ernestine the Telephone Operator
And this is a gem if there ever was one: “The point isn't to use the rotary dial every single time I want to make a call, which would get tiresome for daily use.“
I am a bit surprised about the short battery time. I would expect that, without a display, the battery would last several weeks under normal usage.
We see the battery on a picture, if it comes from Adafruit, that seems like the 2500mAh one they sell. There's no reasons that thing can't last at least a week, but I can understands it wasn't the goal at all to make it last, so almost no effort was invested in that.
A lot of that wizardry is not really user-visible. Ensuring that chips spend more time in sleep mode, coalescing events so that wakeups happen together, ensuring that there are no components passively draining power, etc.
It's like how non-software people can't fathom that it costs $50k to build a relatively simple phone app when MS Office only costs a couple of hundred bucks.
If anything, it's even possible that the cheapest phone has the most engineering done on it to optimize the battery life, due to the fact that reducing the battery size (and resulting cheaper BOM) on a cheap device that has millions of units sold is worth the additional engineering time to reduce power consumption.
The problem here is potentially a software bug. The cellphone radio probably is not getting put to sleep as long as it could be, and that's about 100 mWh.
(Scared of looking dumb, I guess) But aside from choking on our tears and those shameless bellyaches, we didn't give him any grief. This would have been probably 1994 - 2000... when my folks upgraded to touch tone and answering machine :)
It's cool project!
The firebrigade and police not even a thousand clicks away.
Maybe I should have clarified that I just meant to highlight the fact it's almost impossible to understand what many of the devices around us are doing because of the dependency on fundamental building blocks which are closed source and have no open source alternatives.
I'm sorry if my comment came out offensive in any way. That wasn't my intention.
I didn’t like the tone, hence the comment.
Do you know a path forward to do this entirely with open source?