The 20th century saw everything from telephones to computers become mainstream. Many of these devices were beautifully designed in the mid-century period, something that’s hard to say about a lot of today’s cheaper technology. [John Graham-Cumming] has shown us one exquisite example, with his teardown of a simple Czech telephone.
The model in question is a DS3600 telephone built by Tesla Stropkov in the early 1980s. Despite this, it’s a design that looks like it hails more from the 1960s based on its smooth curves and rounded features. It’s a rotary dial phone, though a push-button version was also produced.
Inside the phone is a simple single-sided PCB clearly marked out with a tidy silkscreen. The ringer and a few capacitors make up the bulk of the circuitry inside the base, along with the rotary dial. The handset itself plays host to most of the other componentry, including the mystery “WNB 068 hybrid circuit” which [John] couldn’t positively identify.
It’s great to get a look inside vintage hardware and see how things were done in yesteryear. It’s particularly funny to think about how simple telephones used to be in contrast to today.
[Thanks to Saint Aardvark for the tip!]
Here is the datasheet for the WNB068: https://elparts.mekweb.eu/ds/WNB068.jpg
Its for the ds3600 phone itself, not the chip
Hey this is Slovak telephone try Google Stropkov 🙃
Looking at the picture I see a ringer circuit only, network in handset? Looking at the jpg I see a 2 wire handset? Or does it support straight line camp on. Phones past Ma Bell aren’t really mid century anyway.
Hard to see, but I remember that (some) Eastern Block phones had a “feature” that by design the microphone was not disconnected when the handset was in the cradle. This allowed the microphone to be used even when the phone was hung up and not in use. This limited Alexa type service, where by your spoken wishes to disrupt the state could be provided for without even the inconvenience of you making a phone call.
You , as every really shitty western guy talking nonsense that was shown on shitty west television for western morons that believe to everything shown on tv. There NO phones with such circuitry. I have teardown for reparation a lot of different models east phones and no one have such idea because of engineering consideration. As well, peoples was not stupid as westerns and if they now this they for sure can easily remove/change it. It was mechanism to spy through phone, but not through microfon and it works with every phone with mechanical ring, including west ones. Its really sad faith to be western this days, its mean washed mind by Hollywood and TV, corporate dictate, high prices and governments that do not care. But this is not excuse for lacking of common sense and believing to any bullshit that appear on tv or facebook.
So lovely!
Where can we find one? Searched on eBay: none…
Search for Tesla Stropkov
I have a furnace thermostat that looks like that!
I have converted a similar one into a kitchen timer… Voltage was a bit low for ringing, but otherwise it worked.
It´s not a Czech phone. Tesla Stropkov was a factory in Stropkov, Slovakia. So it´s either a Slovak phone, or more accurate a Czeckoslovak phone.
Australians are notoriously poorly educated, especially about geography, but c´mon, you´re writing articles and never ever check the accuracy of what you write. Thumbs down.
When you let ChatGPT write your articles, it´s anyway better.
Interesting… I wonder if all the circuitry in the handset was to make it interchangeable among different form factors: phones became more electronic instead of electrical around that time, maybe they wanted a handset that could work with newer designs while being backwards compatible to older style bases.
Or maybe it’s an amplifier? Or does something else to improve sound quality?
Its hybrid circuitry that divide incoming from outgoing speech i.e making from 4 wires 2 wires that go to phone exchange. . I’m really sorry for the new generations that have absolutely no idea what was before thei born. I for really see the case where (stupid) young guy dont know how to dial with rotary dialer and try to press digits. Our (old) generation was not so stupid and know what was before us and we clearly know that world not begin with us and will not end with us.
The hybrids are done in ann IC later
It’s less that we were so much cleverer than the younger generations and more that rotary phones were ubiquitous when we grew up. We had endless opportunities to see people operate them at home, in school, in movies and television, and to play with them from a very young age.
It’s no different than the apparent ease with which younger people seem to ‘get’ tech now: they’re surrounded by it literally from birth.
Yes. That is a very good point