Russian phone dialler using interesting magnetic memory tech

Russian "Trill-2" phone dialler using the same magnetic memory tech as used on the Apollo flight computer.

[mikeselectricstuff]

Before anyone else comments, yes it will be heading to Sam ( Look Mum No Computer)

[yanikkunitsin]

Russian word for "firmware" and process of updating/flashing a firmware to this day is "прошивка" - "sewing in", exactly for this memory type.
And Soviet philips-like screws were notoriously shittty because lack of real standartisation, wrong alloys, bad manufacturing a were basically only used once. You may even call them anti-tampering screws.
Proper machinery and electronics only used flat-drive screws.

[Alexagrigorieff]

К155 chips are TTL, equivalent to 74 series (not 74S or 74LS yet). 74LS would be К555, and 74S would be К533.
ЛА1, ЛА3, ЛА7, ЛА8 are different configurations of NAND gate with open collector output.
ТМ2 is a dual D-flipflop, equivalent of 74x74.

[EEVblog]

I wasn't guessing rope memory, that's hilarious and kinda great!

[KrotowX]

During childhood and school years seen these in my parent workplaces and in other Soviet offices. Knew that these devices are related to dialing, but didn't knew in detail. Thanks about explaining.

[almostanengineer]

Oh hell this needs to end up in the ‘This museum is not Obsolete’ along with the rest of telephone stuffs, even if it’s just a loan.

[sarahjrandomnumbers]

Handy for those times where you have to call 40 people at the Politburo to get authorisation to requisition a new potato peeler.

[JensAndree]

I never expected a dialer to use DIY rope memory programming but now that I've seen this it's actually a really clever implementation, for sure cheaper and way more reliable than the cheapest option for adding digital programmable memory back when it was made. Many thanks for making the video! The weirder the technology and product you take apart, the better the videos!
As a fellow light art installation/hacker I obviously love all your LED related posts - especially since you're doing such large scale installations, but one of my favourite videos is the RAF Sepecat Jaguar gyro. The level of engineering in those gyros are some next level stuff...
Also - love your tea cup! :D

[gordonwelcher]

Your teardowns are the best.
So many interesting devices that you get your hands on.
The descriptions are quite accurate unlike others.
Your pace is quick yet thorough, you don't waste time to teach basic electronics that
everyone knows. It is good that you skip the unscrewing parts
Much appreciated.

[NillKitty]

This is how ANI-B used to work in the US; which was used when your local phone switch needed to obtain your phone number and send it forward (as tones) to a centralized billing system (e.g. CAMA). They ran your physical phone line through a series of rungs corresponding to the last 4 or 5 digits of your telephone number; and when your switch connected to the accounting system trunk, a polarity reversal triggered your local switch's register/sender to bring in the ANI-B system, apply a high frequency tone to your line, and detect which digits (in which positions) to register in the marker [IIRC].

[yoksel]

The logic chips are 7474, 7400, 7401, 7422 (none of that 74LSxx rubbish). The transistors are indeed germanium, and quite obsolete for '85 (МП25). In fact the entire design appears to be based on what was available back in ~1975 in Soviet Union.

[MrMaxeemum]

How about donating it to Look Mum No Computer on YouTube? He has a small museum and might be interested in displaying it.

[zakhars]

Неожиданно) спасибо за обзор, я прям вспомнил детство, МП39-МП42, к155ла3, схемы в инструкции, все такое родное)

[SeanBZA]

Have an even older Japanese version that can handle 20 stored numbers of up to 12 digits, using figure 8 shaped ferrite cores, and all discrete transistor logic inside.

It works by running a single sense wire through all the cores in a row, and then generating a current pulse through the digit wire, and having a counter generating the dial pulses, running through the pulses till the sense wire for a digit stops the count. End of number is another core, that does an inhibit of dialling before the first pulse is created, unless you are using all 12 numbers, which automatically does the inhibit on the end of the last digit. Was used for many years in a pharmacy to call suppliers, storing all the common numbers for them, so the pharmacist did not have to look up the numbers, instead having memorised which button was the desired one.

Press the button and press start, and wait for the speaker to have the ringing tone, or a busy tone, and then, if busy, you pressed reset, which dropped the line, or picked up the phone, which also reset the device, but also connected you to the line as if the device was not present.

Old, dates from the 1970's, and all very crusty inside as well, but a fascinating bit of by now very crusty yellowed beige plastic and old SRBP board, with dozens of small separate soldered in daughter boards, some potted, some not, and not an IC anywhere in sight in it. All boards are tinned copper traces.

[TrebleWing]

Came from Look Mum No Computer. Both are very fascinating vids! Thanks for getting into more of the metal. I loved hearing about it and seeing this clever tech~

[TimoNoko]

These weird mega-jumbo magnetic rings were standard issue in Russian military equipment. That is how they stored parameters in the tube-based missile controller I was fiddling with while in Finnish Army in 1970s.

[gregorymccoy]

Brilliant solution given the tech constraints they had. I'm impressed.

[gordonwelcher]

Such a unique design, you would not expect core memory in this kind of device.
The engineer did a great job bringing his idea to life.

[leosbagoftricks]

Love this! Reminds me of the "Tormat" memory used in Seeburg Jukeboxes to remember the song selections. Tormat = toroid matrix.

[equipmentissues]

I dismantled lots of Soviet equipment in early 90s. I'd say this design is somewhat 70s not 80s because of transistor choice. In 80s they would've used KT315/KT361: silicon BJTs and way more compact.