How & Why Phone Sounds Are Made - Telephone Tuesdays

Today on Telephone Tuesday @hackmodular talks gones!
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#vintage #telephoneexchange #restoration #telephony #telephonetuesdays #tonedarms

[@brumd]

Funny how much emotional response i got just now hearing the UK ringtone. I grew up in The Netherlands, so our ring tones were different. Foreign phone calls were pricey, so it wasn't something you'd do every day. Calling my friends in the UK was something special and exciting, and that excitement began with hearing that strange, foreign, ringtone from a country 'far away' And I just re-experienced that feeling.. Probably something completely unimaginable for someone younger who has never lived the pre-internet era. Thanks for the memory!

[@MrMaxeemum]

I kept our BT746 rotary phone from the early 80's for nostalgia purposes. I can't help playing with the dial occasionally dialling my friends numbers which are still etched in my brain, I can't remember my own phone number now but I have at least 8 numbers I can't forget from back then.

[@kaitlyn__L]

Same, except vice versa - those EU mainland ringing tones were the gateway to an expensive and rare experience!

[@Justin-TPG]

Same here. I used to call the US and Canada a lot from around 1999 to 2004 (praise be for cheap prepaid call cards) and hearing that tone again brought back a deeply buried feeling of excitement talking to people I knew back then.

[@Stjaernljus]

my favourite telephone sound is people who in the early to mid 00s took up their phone operator on getting a song of their choice as the call waiting tone and now cant change it back because the service to change it was shutdown in the late 00s(even for customer service).

[@DasGanon]

I did that but blessing/curse it got changed back at some point. "Ringback Tones" was what Verizon called it.

[@1marcelfilms]

my favorite sound is when 5:48

[@unkowndata2338]

I loved the Verizon Ringback tones. Those were fun.

[@binky_bun]

AHH the busy tone. I know that from calling my doctor

[@scheibenhonig360]

The UK ring tone immediately takes me to Pink Floyd's The Wall. Immediately before "Mother do you think they'll drop the bomb"

[@W1RMD]

"There's a man answering, and he keeps hanging up!" Nice operator, rubbing it in like that. I'm thinking, no s#%t lady! I can hear him!

[@Nev-1957]

The Australian tones are identical. I remember seeing identical diagrams in my training manuals. One of my routine tasks in the exchange was to check the ringing machines and lubricate the cams. We also changed over the active / standby machines on a regular basis to check the operation and share load. If a subscriber ( sub ) left the hand piece off hook we could send a very loud howler tone down the line from the test desk. I enjoyed using howler when it was required!

[@hughjass138]

It's amazing to see how all of this worked. My late grandmother, in her younger years, worked for a company called "standard telephones" where she tested the lines in the old operator stations, before everything became totally automated. One thing i have not heard in a very long time too, is when you dialed a number wrong, and that three chime tone came on, followed by "the number you are trying to call is not recognised. Please hang up and try again". As well as the alarm landlines used to have when you left the handset slightly off the hook.

[@kaitlyn__L]

I’ve heard the latter one a few times on mobile phones, but was shocked because usually it just cuts you off with the repeated same tone! I think it must’ve been running through (one or more) relays, so that my connection point wasn’t cut off despite the final destination failing.

[@Tomsonic41]

I have one of those call-blocking devices to minimise all those sales and scam calls from Indian call centres. It actually answers the phone with the three chime tone before asking you to press a number to make the phone ring. This fools most autodiallers into thinking our line has been disconnected and they remove us from their list!

[@jagmarc]

A place where I started working in early 80s repaired cordless phones and answering machines occasionally but then suddenly pallets of them came in. To test one was repaired it was plugged into a regular phone line socket and called from another line. So being on bonus piecework and seeing an opportunity over a couple of dinner breaks I built a test phone exchange simulator out of bits and pieces including a film projector, cassette player, and spare parts for TVs and stereos. After I kept finishing my week quota early the boss demanded my circuit design so he could get some more made up for others. Such a laugh workibg there in Cartwright Rd Stevenage.

[@dansheppard2965]

We used to get an "All Lines to Luton are Engaged" regularly. It was a bit of a mystery as a kid because we didn't live anywhere near Luton or know anyone there!

[@jameswalker199]

It's a bit of a mistery why anyone would want to live in Luton in the first place.

[@FrankJohnson-ye8lt]

That brought back some memories of my time as a telephone exchange engineer in the 60s. I seem to remember that there were 3 ringing tone feeds but only 1 ring current feed, both over the same 2 second time period. If so, this meant that if someone (usually an actor) said, "I'll let it ring 3 times so you know it's me", this was rubbish! It might ring the bell once, twice or thrice!

[@frumbert]

When I was a kid (late 80's), we had a party line. No tones there - you'd lift the reciever and see if anyone was talking already. Winding the handle would just ring a physical bell at the exchange, and Beryl would pick up and ask who you'd like to be connected to (usually just by name, since she knew everybody anyway and knew which line the call was coming from, and sometimes would even tell you that they weren't home today!). We skipped the rotary phone era altogether and they replaced the single-overland wire with fiberoptic and digital handsets.

[@a4000bear]

I'm Australian, and have been around for many years so I remember all the older tones associated with rotary dial telephones. Australia followed UK practice very closely, so all the tones in your video sound totally familiar to me. However, there were a couple of differences. Tone dialling was introduced in the 1970s - 1980s. The new AXE exchanges used the new higher pitched dual frequency dial tone right from the start. Some of the older crossbar type exchanges were retrofitted to accept tone dialling, and if enabled on your line (you had to request it), your dial tone changed from the old 33Hz 'Brrrr' to a simple continuous 400Hz tone - basically like your 'number unobtainable tone'. I remember requesting VF dialling (what Telecom Australia called tone dialling) when I first got my phone in 1982. As I was on a crossbar exchange, I had that plain 400Hz dial tone, which confused quite a few people when they used my phone! While I haven't heard a 33Hz rotary dial tone since the early 1980s, I never recall hearing 50Hz versions of it. The other different tone was for both 'number unobtainable' and for indicating failure of your call due to congestion. It was identical to the standard busy tone, but every alternate beep was much quieter than the other. One other tone that was commonly encountered were a series of short 'pips' heard at the instant the called party answered if it was an 'STD' (Subscriber Trunk Dialling) call. This indicated that the call was charged on a time basis as it was a trunk or long distance call.

[@stellamcwick8455]

My mom was an operator for AT&T back in the day. She would have loved this channel.

[@Simple_But_Expensive]

Mixing two frequencies actually generates four frequencies: f1, f2, f1+f2, and f1-f2.

[@Luchoedge]

8:33 This sound just reminded me of the theme song of a public tv show I watched as a kid, in the 90's called "Caloi en su tinta" (Caloi was a renowned cartoonist) the show was about art and animation shorts. After a quick search, I can share with you the song title: The Penguin Cafe Orchestra-Telephone and Rubber Band Go give it a listen! I know you'll love it.

[@Colin_Ames]

I did listen, and enjoyed it. Thanks!!

[@Reaktanzkreis]

I´m in germany. Our ringing tone is a 425Hz tone , 1 sek on, 4 second off. It can be also 450Hz, depends of the equipment manufacturer. The busy tone is an interupted tone similar like the UK one, but 480 msec on/off. The congestion/ equipment at the end of capacity tone is 240 msec on/of. The frequency of the the tone is 425 or 450 Hz. The dial tone is a continued tone 425 or 450Hz . A number anobtainable tone is a sequence of three high pitched tones or a announcement "kein Anschluss unter dieser Nummer" means like this " the number you´ve dialled is not in service" PABXes got different tones , depends on the manufacturer. But the dial tone at most PABXes here are three short pips like the "S" in Morse Code, 0,5 sec signal/ pause followed 1 second pause, frequency 400-450 Hz. It´s a mystery, since I got IP telephony few month ago , my phone stuff (AASTRA/MITEL) got an UK dial tone and UK ringig tone, even the phone bells rings to UK cadence. No, i´m not a customer of a british phone company....

[@sw6188]

Here in New Zealand the dial tone was a continuous 400 Hz. Ringing tone was 400 Hz + 450 Hz with the usual brrr, brrr - pause - brrr, brrr - pause. The 'number unobtainable' tone was: dit, dit, dit, dit - pause - dit, dit, dit dit - pause - dit, dit, dit, dit etc. The dits were 75 ms long with a 100 ms gap between them and the pause was 400 ms long. The tone was 400 Hz.

[@gcewing]

Also I think the at-capacity signal was the same pattern as the busy signal but a higher pitch. Or maybe it was the same pitch but shorter beeps? It wasn't something you got to hear very often!

[@sw6188]

@@gcewing I don't think I ever heard it and I don't have any record of the tone pattern, frequency or cadence.

[@hackbyteDanielMitzlaff]

German ringones were/are a bit different. First and foremost, we only (mostly) have just _one_ tone frequency, 425Hz. A dialtone after HookUp is a single continuous 425Hz tone. (1 TR 110-1, Chapter 8.1) A special dialtone (Sonderwahlton) is a exception with a 425+400Hz continuous tone. (1 TR 110-1, Chapter 8.2) A ringing tone (german "Freizeichen/Freiton - "Free Signal/Tone") is 425Hz with a single tone for one second, followed by a pause of four seconds and repeating. (Wich is the same pattern which gets sent out to the terminating end for the ringer. ;)) (1 TR 110-1, Chapter 8.3) A busy tone is 425Hz with 480 miliseconds tone, 480 miliseconds pause endless repeating. (1 TR 110-1, Chapter 8.4) A "Gassenbesetzt" tone (trunk busy) is 425hZ 240ms tone, 240ms pause endless repeat. (1 TR 110-1, Chapter 8.5) A "Aufschalteton" (attention tone, someone plugged itself into the conversation - like a operator or such) is: 425Hz 240ms tone, 240ms pause, 240ms tone and 1280ms pause(?? maybe to give the original party time to switch topics? lol ;)). (1 TR 110-1, Chapter 8.6) A "Anklopfton" (call waiting tone) is: 425Hz 200ms tone, 200ms pause, 200ms tone, 1000ms pause, from here on; 200ms tone, 200ms pause, 200ms tone, 5000ms pause and repeating as long as the third party waits for answer. (1 TR 110-1, Chapter 8.7) And then we have the other tone besides 425Hz which is a "Hinweiston" (Probably called "Special Information Tone / SIT in english?;). (1 TR 110-1, Chapter 8.8) Which goes as follows: 330ms 950Hz, 330ms 1400Hz, 330ms 1800Hz, 1000ms pause for variants without voice message With voice message 1600ms pause after the three tones followed by a message of whatever sorts is needed. ;) (Like, number no (longer) available or other things. ;)) There is a complete set of samples and a nice description on the german wikipedia under de wikipedia org wiki *Hörton* Have fun .. and keep it up, all of you museum people!! ;)

[@cannotbeleftblank6027]

Ah yeah, the 3 rising tones whenever you called a wrong or disconnected number. A real strong indictor of "oops, something went wrong".

[@hackbyteDanielMitzlaff]

@@cannotbeleftblank6027 Aaand actually, what i translated as "Gassenbesetzt (trunk busy) is also equivalent to a equipment busy tone... You just don't know where the call fails.. Except if you can fully dial, and after a few seconds comes the SIT .... then you _still_ don't know s.. ;)

[@Ulthar_Cat]

Hi. I'm from Mexico and I'm 40 years old. When I was a girl all the tones were the same note. Everything: the dial tone, the ringing tone, the busy tone, they were all the same. You could even tune a guitar with it because it was a perfect A. Cool. 💜

[@williamcrann155]

I’m a student nurse and in the hospital I work at we have an internal phone system that still has operators. We have a digital voice recognition switchboard but when it doesn’t recognise your voice you can ask for the operator and it puts you through to a real human who directs your call!

[@KarrrRep]

My sisters boyfriend back in the late 70s was a telecommunications engineer and took me to see our local exchange watching the dialing mechanism in operation.

[@markshark9162]

I'm from the US, but I'm very familiar with the ring tone used by your exchange from Pink Floyd's music. I think today is the first time I've heard the modern tone, however. Thanks for sharing!

[@Aussiesnrg]

That was great. Similar sounds to early Australian phones

[@christhomas7905]

Oh gosh I have just found a new KZbin channel I'm gonna binge-watch at night now! I love telephony, I own and have restored a Bakelite 312F telephone. I also really want your telephone exchange in my garage lol 😁 I'm now gonna search for all your other videos. Thank you for making these!

[@tortysoft]

I used to work on those Strowger exchanges. The ring tone generator was very large and was mechanical - on the floor.

[@RR4711]

My family lives in Australia but we have relatives in Hungary. We usually call their landline phone through Skype as it’s the cheapest. There’s always a moment of confusion as the ringing tone sounds like our busy tone.

[@wideyxyz2271]

When I was in the "Cubs" back around 1970/71 to get one of our badges (I forget which) we had to make a telephone call from a public phone box. Back then they were 2p or 5p coins depending on the length of the call. You got so many minutes per coin and would get an intermittent beep if you had to put more coins in the box to continue the call. Back then a Twix bar was 3p so a 2p phone call was a lot for a 7 year old kid!

[@mitchese1]

Kind of neat to think that everyone's ringing tone or busy tone was synchronized at exactly the same time. I always thought it was per-call (so the busy tone would start after you finished dialing), but looking at how it's built, there is a constant busy tone that you just tap into when you call a busy number

[@tcpnetworks]

Depending on what exchange... In the 1980's we switched the AXE which generated the tone on-card. 4 phones technically shared the oscillator outputs per card. By this time, the oscillators were a few components stacked around a computer controlled frequency generator, which could generate almost unlimited dial tone types.

[@mickcoleman5396]

@@tcpnetworks or System X

[@eDoc2020]

I'm not sure about the tones but the interruption of the actual ringing was split into multiple groups. In the US the standard ring is 2s on 4s off. So 1/3 of the phones would ring in perfect sync, then the next third, then the last third. The offset means the ring current generator only needs to be 1/3 the size as if everything was in sync.

[@brianstoynancy9630]

You can see that near the end of this video, when he is demonstrating the cams which produce the ringing cadence. There are three cams, separated by 120 degrees, so that three lots of ringing are sent out per revolution - effectively 3 phases.

[@DustyCustard]

There was also a chirping 'pips' tone when someone was calling from a payphone, to let the caller know the call was connected and to now insert 2p.

[@mickcoleman5396]

And you couldn't get the 2p in and it timed put

[@Justin-TPG]

Ah, the tremendous annoyance of being a child in the '80s and having to call home then hang up after a few seconds to let them know I was on the way, only for someone to ninja to the phone and pick up, depositing and wasting my valuable 10p or 20p coin

[@leiflang8097]

I live in Canada but the UK ringtone is easily my favorite

[@dillipphunbar7924]

Brilliant! Thankyou for explaining that. I remember getting up in the early hours on special ocassions like Christmas , to call aunt and uncle, and grandparents back in UK, from Queensland Australia. I think the dialling tone was subdued , slower than local calls and maybe a lower frequency of pitch. This was during the 70s and 80s. Perhaps in another episode, you could "attempt" to explain to us how the USA President was able to make a call to the astronauts on the moon?

[@stackersmbe852]

I love the see you next Tuesday.. nice cheeky finish

[@sivoltage]

OMG! I love this so much, very well edited, fascinating analog madness!

[@stevenmayhew3944]

In the USA, the dial tone, once a 60Hz steady buzz, is anymore a Middle-F/Middle-A dual tone, creating a beat tone of Contra-F. A busy signal happens once every second, and a line-disconnect signal happens every half second, both at 50% duty cycle. Again, once 60Hz tones, now at Middle-Bb/High-D. Nowadays, if a line is disconnected, you hear a three-tone ball-buh-beep followed by "We're sorry. The number you have reached is not available at this time. Please check the number and dial again. If you need assistance, dial the operator. This is a recording."

[@mickcoleman5396]

It was a common misconception that the ringing current sent to the called customer and the ringing tone sent to the calling customer were the same or they were in sync. Some peole would use it as a way of communicating erroneously. "When you get in give me three rings so I know you got home safe". (you didn't want to answer as it then cost money) But it might end up one ring or four and cause confusion and the called customer would end up answering, which defeated the object.

[@graemedavidson499]

Speaking of tonewheels, The Telharmonium is worth looking up as, amongst of the first electronic instruments, it played directly over the telephone network!

[@theotherwalt]

You might be interested in the book The Cuckoo's Egg. It is about the first known international (USSR/USA) computer hacking. The hacking was with old school, dial-up modems. The author, had to use some phone switching hacks to know when the hacker was calling his system. The origin call was traced back to Europe. To discover where the hacker was coming from, they had to trace through an old electrical-mechanical phone exchange in West Germany. The book might be of interest to you, for the phone exchange systems.

[@camofilms]

Very clear to understand, thanks

[@jameswalker199]

One memory I have is leaving a phone off the hook and hearing these three notes, rising, followed by "please replace the handset and try again". I always wondered how they knew to send that message. This was the DTMF days, so they probably just had a programmed timer somewhere that said "has the line been opened without a successful connexion for > _n_ seconds?"

[@jameswalker199]

From what I can find in Tone Def, it's the "special information" sound.

[@Graham_Rule]

When I was a child we shared a phone line with my grandparents who lived just up the road. Mostly our phone rang when my grandmother turned the handle on the side of the mini-exchange in her hall cupboard. Usual phone bell but cadence entirely dependent on how much she turned the handle.

[@onefish26]

"What makes the ringing sound?" Bells Sam... Bells make the ringing sound... 🤣😂

[@tehklevster]

I love these Telephone Tuesdays. Back in the 80's my town library's reference section had a full suite of those telephony books and I used to pour over them for hours rather than turn up to college for Business Studies and Accounting. Wish I'd nicked them, because no-one else was reading them.

[@tomholroyd7519]

I love how Star Trek NG used auditory cues all the time for everything.

[@madmodders]

When you pick up the phone here in Sweden and before any number is dialed, you hear a continuous 425 Hz tone. And if you dial a number and the connection can't be made for some reason other than busy or congestion, you get the "special information tone" consisting of three consecutive tones at 950 Hz, 1400 Hz, and 1800 Hz. (0,332s tone, 0,024s pause)x3 + 2,0s pause, repeating 5 times. If the number doesn't exist, it's the same tones, but with 1,0s pause between repeats wich are only two times, and then a 15 seconds pause with a voice saying "please dial 90120 for information". Not in english though obviously... 😄

[@adecarnally5501]

Brilliant! Thanks for this!

[@DeadKoby]

Now that Voip is the thing......... you can emulate whatever country tones you want.

[@KmF0X]

Here in France, picking up a phone gets you a continuous 440Hz Useful for tuning an instrument, I guess XD

[@Colin_Ames]

Thanks for another very informative and entertaining video.

[@kaitlyn__L]

I always preferred the two-tone ring tones, as opposed to single-tone beeps. But then I love beat frequencies. The Japanese one has such an interesting texture due to the large difference in frequencies, almost sounds like Dalek-y ring mod sounds. Haven’t thought about how rarely I’ve heard a dial tone. Ever since my family got cordless landlines, where you could dial ahead of time, so it must be about 20 years now.

[@eDoc2020]

If you pre-enter the number on my cordless phones you still get about a second of dial tone before it plays the number tones. I thought all were like this. Did yours have some sort of digital link to the phone company?

[@kaitlyn__L]

@@eDoc2020 no, it just had a regular hookup. I do recall it muted the output for a while though, to hide the clicks and such. IIRC you could even turn off hearing the actual dial tones (since if you needed to check the number, the screen’s always there).

[@TheBigChill1]

The tones in my country where basicaly the same as in the UK... Our first telephone company was a British joint venture... Anglo-Portuguese Telephone and Telegraph Company... I stated on the telecom business on my late teenage and have seen all the change from the Stronger system until the digital age...

[@SuperBROKEN81]

How many people remember getting an answering machine from radio shack?

[@Richardincancale]

Before the French network got digitalised in the 1990s we’d hear a stuttered tone while you waited for the line finders, and that could last quite a long time indeed due to congestion / aged machinery before you got the actual dial tone and could proceed. It was quite odd being used to the UK network where the dial tone would be present by the time the handset reached your ear!

Absolutely enjoyable! Keep on doing this series. Thanks.

[@GadgetUK164]

Very interesting and amazing you are sharing all this info so it doesnt get lost to time!

[@telocho]

The ringtone would come from the remote exchange (where the called subscriber is) so as a clever side effect, for the caller it is also a way to determine teh quality of the (analogue) speech path before an answer. Voip generates all ringtones by the local phone itself so this is no longer the case.

[@christianherald]

yay Mitch; the phones and tones are cool but he really sells it; such an excitable looking fella, an absolute joy; and of course, ...next tuesday

[@grishka212]

In Russia the dial tone was definitely higher pitch. I don't think our tones differed in pitch at all, only in rhythm. How people call them reflects that too, "short tones" (busy, also heard after the other side hangs up) and "long tones" (ringing).

[@ropo2467]

In a pinch I used to tune the guitar using the dial tone. I realise now when checking that 425 Hz isn’t really the correct string tuning, but at least it was close enough. And apparently 425 Hz tuning is a thing that some guitarists use. I wonder if there is a connection?

[@svofski]

Evan Doorbell coop please!

[@sonicase]

how about the annoying "receiver off the hook" sound

[@Poebbelmann]

Penguin Cafe Orchestra - Telephone and Rubber Band

[@Tomsonic41]

At around 4:06 when you show the ringing tone, I can faintly hear the busy signal in the background. I remember this very well when using phones in the 1980s and 90s - our local exchange wasn't modernised until around 1995!

[@NataliaBazj]

International Telecommunication Union Recommendation E.180/Q.35 Technical characteristics of tones for the telephone service.

[@LostDeadSoul]

My dad told me. If you need to tune an instrument, you can always get an A# from there. Faroe Islands used 440Hz

[@garethhughes6739]

See you next Tuesday? Cheeky!!

[@SDWNJ]

Once when I was in my late tens or early 20s, I was in the process of rewiring a phone jack and was holding the bare wires and the phone rang and I got zapped.

[@luminousfractal420]

the telephone and the doorbell. ✊ next question...

[@alexandremargat2350]

In France, thé idle tone is a continuons 440 Hz tone. When calling, same frequency, 1.5 s and 3.5 seconds of silence. The phone you want to reach is unavailable? 0.5 sec AT 440Hz, 0.5 of silence. Very useful if you wanted to tune your guitar back in the days.

[@optroncordian7863]

In my country there was roughly 440 hertz for everything, just interrupted in different rhythms for different states. When ready for dialing, there was a signal like the morse letter A. If it was a company or enterprise or hotel exchange (private exchange, basicly), it was the morse letter S, so you will know that this phone is not connected to the national network. The busy tone was the letter T sequentially. The ringing tone was a one second tone every 10 seconds. The ringing signal was 25 hertz, 110 volts, generated by the dynamotor and it followed the ringing tone pattern. Later the dynamotors were replaced by solid state devices. Curiously, there was not a standard to follow about the tone frequency, so there was noticeable difference in the tone pitch between each exchange in the city. At some point I was able to recognize the exchange to which a user was connected just by picking up their phone and hearing the tone. When digital exchange came, the difference was the dial tone, which was a continuous one, and the ringing tone and ringing signal, which were one second every five. Cannot remember their tone frequency, it was significantly different.

[@ShawnTewes]

Up until some time in the early 90s some Latin American countries (and in Central America where I live) used around 360 Hz, which to my ears sounded so overdriven that you could faintly hear other tone patterns in the background when the phone was ringing (possibly from a different ringing machine, such as a backup, or neighbouring tone settings on the knob bleeding through). It was almost like a distorted pulse or triangle wave. Later on they switched to the now common 425 Hz at a much more reasonable volume level.

[@davidf8749]

Great informative video of a bygone era. You could probably do all that with an Arduino Pro Mini these days but it's fantastic to see the electro-mechanical solutions of the day. :)

[@AM-ui9mc]

I remember you could pick up the phone to tune your guitar I Sweden. I wonder if we used 440hz?

[@Beinlausi]

In Germnany, it was flat.

[@padders1068]

Thanks Mitch, yet another interesting and informative video. I'm old enough to remember rotary dial telephones, which sent out pulses, and in todays terms seem so slow, but at that time they were top of the range technology. And there's always the irony of 999, which took the longest time to dial of any 3 digit number. Thanks for sharing! 🙂😎🤓

[@jackiesmith-vb5gw]

i used to love letting to dial tone run out and if you were lucky with crosstalk, you could hear other conversations! phone boxes were the best for this!

[@Tomsonic41]

That is something that I remember clearly from using phones in the early 90s. The dial tone would stop, there would be several seconds of silence, then for about 2 seconds you'd hear the noise of the selectors moving about, pulses, even snippets of other people's conversations before the line went completely dead again. I really wish I'd recorded some of that, but I didn't have an easy way of recording the telephone signal to a cassette tape back then.

[@JonBrase]

Weirdly, I just hear the heterodyne tone in the US dial tone, while my dad hears one of the original tones.

[@markedis5902]

Another episode of me feeling old

[@michaelmiller641]

Fascinating, that last green phone was the one I had years ago, I think you rented them from BT!

[@DavidWright-yu7bi]

The Penguin Cafe Orchestra mixed some busy tones with a rubber band for their track Telephone and Rubber Band: kzbin.info/www/bejne/iIi9ZaOsmpqAocU

[@a4000bear]

That music was used in a 1986 Australian movie called 'Malcolm'

[@EDDIE.EDDISON]

So… with so many ocillators, does this mean old telephone exchanges were synthesisers? 🤔

[@DISCOTECHS]

The ringer 2A (UAX13) has a very eerie sounding ringing tone, unlike some of the other ringers such as 44A. If you ever get a chance, please can you put it into a spectrum analysrer to see what the components are in the way of sine waves, that need to be mixed to create the exact sound electronically. I would like to see if it can be simulated with oscilators and filters, rather than "Wav" recording it.

[@berndeckenfels]

What about. All ended - I know that in some systems you just get dead sound, in some you cannot even hang up if the other did not hang up - that of course changed with the electronic exchanges, (latest?)

[@robertschnobert9090]

The tones sound different where I live 🌈

[@chrisprobert6]

😅 tumultuously tuesday again... Woooohoooo

[@sparkyprojects]

All the tones are generated at the local exchange, the ringing current as you said were on a different machine at the destination exchange ;)

[@matthehat]

When is Sam doing a cover of Telephone and Rubber Band by Penguin Cafe? I'd love to hear that

[@chrisprobert6]

10:49 most apparent on a friday afta 5pm😂

[@BadgerRobot]

Big audio flashback moment when you played the US version.

[@MrMaxeemum]

See you next Tuesday? Why I auta!!!!💪💪💪

[@davidburke1794]

The USA had ve a 3 tone progression normally before a pre-recorded announcement.

[@gwesco]

That is called the "Special Information Tone." I have two Nortel announcement players that have switch settings to enable that for messages like "the number you have dialed is not in service." I was a telco tech for 32 years.

[@loopinnerthe]

We only saw your LFO contacts. What was inside making the actual tones? Mitch thank you for all your hard work and research on this one. You are like the driver on the footplate of a steam engine, that lets us kids up on board to have a look into the fire box.

[@Lugeix]

Its 30 in US.

[@Beinlausi]

I've got the same oscilloscope! xD

[@MinorLG]

I'm an american, and I'm old enough to have had to double cancel a call, because the selecter didn't find a line

[@mickcoleman5396]

Mitch, nice to see the explanations. The ringing current (used to make the bells in the called customer phone work) is 75v AC in director exchange, is that the same on a UAX?

[@weapea]

Hammond organ mentioned 😋

[@Madness832]

A few days ago, I made a call, to the UK (from the States), and it rang w/ an American-style ring. I was expectin' the UK double-ring, so I found it odd.

[@stephencampbell9384]

The beat between 130 and 400hz is 270hz which is not lower than 130

[@mattsan70]

do you have any DTMF decoding in your exchange or just pulse decoding?

[@genafk]

The ringtone at 2:28 is the same one that we had in Australia, though our SxS were either pre-2000 or 2000 type selectors, cant remember which ones but one of the models had some problems, large SxS systems had uniselectors for incoming customer calls. As far as i know talking to telecom engineers, cities had changed to ericsson-siemens crossbar switches later and small rural area's were served by SxS switching systems until they were ripped out and changed over to early digital systems. By the way, do you have any wiring schematics or diagrams for a single unit of a SxS switch? I have been doing research into the possibility of making one brand new switch just for fun but not sure if the relays are special or generic ones, nor how they are wired, interested to know if such documentation exists. Cheers.

[@brianstoynancy9630]

@genafk: the relays used are not generic, other than the style of construction. The coils vary in number and resistance, and the contacts are built up to suit the switching functions required of each relay. I have some circuit diagrams, but they are for a later version of the step by step 2 motional selector mechanism, and would need to be changed for the more common mechanism shown in these videos.

[@juno6]

Kraftwerk's The Telephone Call is full of these sounds...

[@davidburke1794]

I was collecting the audio of when there is fault or miss dial or other failures. I have one for not enough coins to make the call.