Old-school rotary phone dials into online meetings, hangs up when you slam it down

We've all been there: A meeting goes sideways and you really wish you could physically slam the phone down and walk away. Maker Stavros Korokithakis knows that feeling well, so he took an old rotary phone and turned it into a device that can dial into - and hang up on - video calls in a decidedly retro fashion.  Armed with an …

[My other car WAS an IAV Stryker]

Well done + random thoughts

Old POTS/PSTN devices are not as easy as banging together some TTL logic or even basic audio. Kudos! ----->

I still hope someday someone will design & build an iPhone dock with Bluetooth and Qi charging [1] so I can use a physical/tactile number pad and handset to make calls without touching my actual phone. Adding USB for a computer -- Teams/Zoom/etc. -- would be quite doable. Maybe even hold some speed-dial memory. You could still slam the call dead and have decent sideband -- like our subject found -- unlike most headsets. [2]

1. When I first thought of this, it was back in the 30-pin days and Bluetooth was still too sketchy.

2. I have an older headset (Plantronics/Poly) that I won't give up because it's sideband is perfect; the newer one (Logi[tech]) stinks in that area.

[Antron Argaiv]

Re: Well done + random thoughts

This person did it

https://hackaday.com/2022/09/10/the-open-source-rotary-cell-phone-two-years-later/

WAY more work than I would be willing to put in, but kudos for completing the project ANd for making it open source!

[Anonymous Coward]

Re: Well done + random thoughts

... or Sparkun Electronics' Port-O-Rotary (20 yrs ago) ...

[Caver_Dave]

Re: Well done + random thoughts

I made one just before the turn of the century with a Nokia 2210 inside - The battery for the ringer was nearly as big as the bells themselves! It could also be powered by a cigarette lighter socket.

I must have had too much time on my hands before children!

I wrote the noise reduction and echo cancellation assembler code for the 2210 many years before, and so had a few lying around that I could play with and knowledge of the development tools.

I had a Land Rover at the time and it looked completely weird with a white dial up phone Velcro'd to the dashboard top.

[spold]

Aren't those...

...what the Doctor Who Cybermen used to wear?

[heyrick]

I have some old phones

One, slightly more modern so it does DTMF, is hooked to my fibre box. The microphone is horrific, an ancient carbon granule thing that barely works any more. I keep wanting to patch in a dinky little electret in its place, but the downside of old phones is they use weird voltages and run as a current loop so...

Still, there's something oddly satisfying about dialling a number. Rrrr-fzzzzzzzt, rrrr-fzzzzzzzt, rrrr-fzzzzzzzt....

[heyrick]

Re: I have some old phones

I should add, about a decade ago I had a lighting strike either to the phone line or a big whack of power was induced in the phone line. Either way, my ADSL box was toast to the point where stuff rattled around inside if you shook it, and pretty much everything connected to the box (Ethernet, USB, or phone) was also crispy toasted. With the notable exception of the rotary dial phone that I had connected because the ringing bell is a pleasing sound. That thing just shrugged off the impact - nothing burnt, nothing damaged, it still works fine.

[collinsl]

Re: I have some old phones

I guess because in the UK at least they're designed to operate on 90V DC and engineers back then envisioned lines being struck by lightning so everything inside is much more protected than a little 12V/5V router with basically no shielding except on the ethernet side when it steps up to 48V.

[Chris Gray 1]

Re: I have some old phones

The POTS exchanges were quite forgiving. I had read somewhere that you could dial using the hook plunger thing. Just tap it N times to dial an N (10 for 0). Worked fine.

Soooo, when I wanted to dial out for a 300 baud modem, just do the same thing in simple code - the hook switch in RS-232 is available. Aaand, you didn't need any kind of modem really, since 300 baud was slow enough that even an 8-bitter could implement a "bit banger", where the RS-232 TX line is simply bounced up and down with the proper timing. Just remember that the start "bit" is 1-1/2 bits long, and you need a couple of off bits between bytes. For incoming, you just counted properly (depends on your CPU speed) and then sampled to see if it was an incoming 1 bit or a 0 bit. Wait for the start bit between bytes, and you stay in sync. Sample at the middle of the data bits. Pretty much how UART chips did it.

[Antron Argaiv]

Re: I have some old phones

Uhh. Old TTY tech here. Start bit is the same as all the other bits, including the stop bit.

Now, *some* older, 5-bit Baudot machines had a longer stop bit, and some even had two bit times for stop. That was to give the mechanism time to reset before the next character came in. But everything that does ASCII has a single stop bit.

Start, data 0 through 7 and stop, repeat as necessary, from 300 through 56k.

[J.G.Harston]

Re: I have some old phones

Yebbut you time 1.5 bits from the start of the start bit to get into the middle of the following bits.

[Inventor of the Marmite Laser]

Re: I have some old phones

Bashing the receiver rest to "dial" numbers worked in coin boxes to make phone calls for free.

So I'm told.

[Jason Bloomberg]

Re: I have some old phones

You could do the dialling on the hook switch but it didn't get you "free". It was an easy enough skill to master and everyone would have been doing it if it had worked.

I believe call charging was handled by sending tones to the payphone.

How it was with A/B buttons I don't know - I remember them but only from my earliest years.

[Anonymous Coward]

Re: I have some old phones

I did encounter various "courtesy phones" where they had disabled dialing by removing the dialing disc. Then that trick did work.

[Inventor of the Marmite Laser]

Re: I have some old phones

Oh I can assure you, it did work. And yes, we ARE talking about A, B button call boxes.

So I'm told.

[Bebu sa Ware]

Re: I have some old phones

Bashing the receiver rest to "dial" numbers worked in coin boxes to make phone calls for free.

Phreaking ?

[heyrick]

Re: I have some old phones

"So I'm told."

Sort of not quite. The big chunky payphones wouldn't let you call out without putting money in. You could, however, pick up and "dial" a number with the handset button. The phone will ring, and it'll disconnect in a couple of seconds after the other end picks up when it understands that no money is forthcoming. But it's long enough to tell "MUM! CALL ME BACK!". Very useful at boarding school.

[RobDog]

Re: I have some old phones

Those sound like Don Martin sound effects from MAD magazine

[Timo]

sidetone came along for free with POTS

The sidetone that was mentioned came along for free - the full voice conversation is carried on two wires and is powered by the telco. There's a hybrid circuit in every phone that gets the microphone and earpiece working on that one loop.

[J.G.Harston]

Oooooo, you shouldn't have had to butcher a phone to do that, it could have been done with interfacing that you could just plug the existing phone jack straight into. In my noughts and early teens I did loads of connecting up surplus rotary phones I was given. Great fun. I've still got a couple of 1926 NeoPhones. Great things, the sound is like talking down a long pipe. :)

[David 132]

Heh, I have you beaten by about 20 years - I have one of these mounted on my kitchen wall. Non-functional (albeit, in much better condition than the one shown at the above link); one of these days, when I Get A Round Tuit, I'll put a Raspberry Pi or something in there and make it a functional Wifi intercom. Its construction is a masterclass in turn-of-the-century electrical design; wires routed through grooves milled into the wood, and held in place by blobs of candle-wax.

[J.G.Harston]

Ooooo.... drool!!!!!

[Bebu sa Ware]

Its construction is a masterclass in turn-of-the-century electrical design;

Very much turn of last century. ;)

I'm just taking the piss as clearly meaning fin-de-siècle.

Curiously I grew up in a village in a house built in the 1880s that still used one of those phones and a village exchange employing local switchboard operators until the early 1970s. "Number please ?"

The two giant 1.5V cells inside the wooden box is an abiding memory. Later when the phones were being discarded we mucked around with the ringer dynamo(?) as you could receive a palpable shock from them.

[Marty McFly]

A piece of analog hardware manufactured in the 1970s....

I have two rotary dial phones in service at my residence. Yes, since I have to drive 8 miles before my first bar of cell service, I maintain a physical wired land line. Model 500 series, one wall phone and one desk phone. Yes, both are "Red phones".

These phones ring with a real bell. And the audio is significantly more clear than the audio on the various digital, wireless, and headset telephony devices I also have. It is actually surprising how much audio quality we have sacrificed over the years.

Cheers to devices built to last!

[Rivalroger]

Later vintage

I've long thought that there would be a market in bringing an old Brick mobile with modern 4/5G but you would have to sell it with stripy shirts and red braces.

[werdsmith]

Re: Later vintage

They are on AliExpress, of course.....

[Saxonbowman]

There are Bluetooth devices that plug into your POTS phone and connect to your Cell. No modification required. I use one called Cell2Jack and it works well with US style modular connectors. iIt allows me to make and receive calls on the cell network. It would only work on conferencing software if the provider had a call-in number.