OT Telephone technology circa 1950

Anyone have a link for technical details around the new fangled Atlas computer, circuitry and programming, at Bletchley Park, England ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Still interesting for a spring chicken (relatively speaking) such as myself.

I grew up with by far more advanced exchanges than that (though still archaic compared to today's gear), but good to see how things were done back in the "old days".

I'd probably be more interested in a more detailed account of how it did what it did. I've always been fascinated how things were done before the luxuries we have today.

--
Linux Registered User # 302622

Same here. I'm going to spend some time searching Youtube for some old Western Electric video if more of it exists.

How long have you been using linux? And are you just as GUI user or have you some more detailed experience. I have one issue that I need to pick a brain on.

Good one. I don't recall the senders being as slow as the one tone-pair per second I heard in the video, though.

I own a few old Telephones.One of them is a Western Electric desk style/office/home phone,which dates back to around 1933.Another one is a brass Western Electric non dialer candlestick phone.A few others are Western Electric desk style/office/home phones which date back to the

1940s and 1950s and and another one is a Swedish Eicophone which I think dates back to the 1960s.A buddy of mine owns some old phones too.One of them is a Western Electric pay phone which dates back to the 1960s.A friend of his who retired from Bell South converted that phone so he could use it with modern Bell South phone system.He used to have that pay phone mounted on a wall inside his garage/shop in his back yard.Another old phone of his is one I traded to him for something.It has a pantograph on it, I think that pantograph phone dates back to the 1940s. cuhulin

Oops...... Senior moment.

I forgot that dtmf didn't come into use in the Toll office I was in until the 60s.

In the video, each step they called out for the sender, represented one to

10 pulses being sent at 10 pulses per second.

Sadly, the most 'real' work I've had to do on it is reconfiguring and compiling the kernel to support my sound card back in the days when it didn't do this 'out of the box'.

Nowadays, I have it in my sig more for historical reasons rather than anything else. I moved to Linux after running a DOS box for at least a decade(and doing things under that which windblows couldn't!), and moved to Windows some time after that due to a software support issue where Wine was simply too slow, and some critical support utilities for this app set wouldn't run under Wine anyway. And before you ask, virtual machine software was not an option (again to due to speed) because of the overall slow nature of the CPUs of the day. (probably a different story today).

You'll notice my headers say Thunderbird for windows, and the reason for this was I had a substantial quantity of stored mail for Mozilla Suite (back before Mozilla split and separated Firefox and Thunderbird) that I could transfer _really_ easily between Linux and windows and still have it work.

Real Soon Now (meaning when I get around to it), I'll be running a Linux box once again (although alongside Winblows) ironically again due to a software issue that's only available under Linux this time... This time around, my use of virtual machine software won't be stopped by machine horsepower, but rather that I've become spoiled for speed (non-shared CPU use) and another box is cheap enough to do this anyway.

Alongside the fact that Windows support (more network rather than desktop) has become my job in real life now, which means I'm likely staying with windows in the future, Linux is going to be (in the near future) merely a means to an end rather than my primary reason for living...

I don't know if that's a reason to slash my wrists over just yet, either way, being of viable assistance to you is unlikely at least until I start setting up and playing with the new app anyway. Though I'm guessing my Linux hacking in that capacity will be limited to well documented stuff anyway.

On a slightly different note, I was going to send this via email because it's venturing enough beyond off topic, but your email addy in your newsgroup header appears to be invalid (at least things at this end appear to indicate that anyway).

--
Linux Registered User # 302622

Why did the button presses sound 'kinda' like DTMF in the video then? They also mentioned it sent series of tones in the video as well. I thought DTMF (in any capacity) would have been very Star Trekish for that class of exchange anyway.

--
Linux Registered User # 302622

Well it is a valid mailbox but since it is on usenet and will get spammed to death everything ends up in dev/null. As far as this being off topic, the subject was marked as OT anyway and I'm sure there won't be any complaints unless it's from a chronic complainer. The question I had has been resolved for now without a good outcome. I'm having a problem with a fire wire controller and the hoops the driver has to jump through to become a serial bus or "tunneled scsi" port. 1394 is supposed to be fully kernel and hotplug supported in the

2.6.x kernel but I'm getting an error with the serial bus module trying to log into the device. Works fine with USB and the ATA drives as they are all tunneled into this scsi bus architecture. So there is some bug that I can't overcome just yet and it doesn't go away with the newest kernel for my O/S. Anyway until I understand how these ports and nodes interact and in what sequence they need to occure (which is very important) I'll stick with USB :)

Well if you know anything about it you know 100% more than I :) All I know is that I used to be able to whistle a decent 2600hz tone and hang connections up amazing my friends. And I've read a little about phreaking and trunk line parties and such. Also have some parts and pieces from some tube powered microwave stuff that a ham buddy of mine who worked for Ma Bell allowed me to snag from a teardown of a relay station.

The answer is that multi-frequency tone signaling was used for inter-office signaling long before it became part of home telephones.

There is an enormous amount of information available at the Bell System Memorial site

In fact, there is so much that it is hard to wade through it all, and the search engine isn't really spectacular. However, I did manage to follow a thread long enough to find a description of Operator Toll Dialing as described in the movie (which can be downloaded from the site), where I found the following description:

"Part of the explanation about how the new technology worked includes a demonstration with sound of the then new "multi-frequency" or MF tone senders. Different and more pleasant sounding than the "touch-tones" used by our phones today, MF tones were used internally by the switching network. Though they're now nearly extinct, MF tones were considered by phone phreaks to be among the most beautiful sounds heard on the old network."

Retired phone phreaks will recognize the bottom two of the operators' keys in the movie. They are labeled "KP" (keypunch) and "ST" (start), and along with the 2600-Hz signal mentioned in a previous post, were the primary control signals for phreaking.

Bill

The answer is that multi-frequency tone signaling was used for inter-office signaling long before it became part of home telephones.

There is an enormous amount of information available at the Bell System Memorial site

In fact, there is so much that it is hard to wade through it all, and the search engine isn't really spectacular. However, I did manage to follow a thread long enough to find a description of Operator Toll Dialing as described in the movie (which can be downloaded from the site), where I found the following description:

"Part of the explanation about how the new technology worked includes a demonstration with sound of the then new "multi-frequency" or MF tone senders. Different and more pleasant sounding than the "touch-tones" used by our phones today, MF tones were used internally by the switching network. Though they're now nearly extinct, MF tones were considered by phone phreaks to be among the most beautiful sounds heard on the old network."

Retired phone phreaks will recognize the bottom two of the operators' keys in the movie. They are labeled "KP" (keypunch) and "ST" (start), and along with the 2600-Hz signal mentioned in a previous post, were the primary control signals for phreaking.

Bill

I wasn't a Switchman (the guys that maintained the switchroom equipment, but as I recall.....

There were many transitions of equipment and methods in the 50s. And there were DTMF pads on the Operator's positions and Toll Testboards, long before DTMF Trunk signaling started. At that time, circuits used a lot of different Trunk signaling methods; Simplex, Duplex, and E&M with and without a SF (Single Frequency signaling) set.

What I recall is that to relieve the Operators from having to use rotary dials, greatly increasing their productivity, Senders were installed to collect digits from the DTMF keypads and to then "outpulse" the digits at 10 (DC) pulses per second, to the Long Distance circuits (over in Toll where we maintained circuits and all transmission equipment). I believe the Senders contained DTMF-to-DP converters to enable this. I only suspect this case, because I helped someone de-bug DTMF receivers in Senders a couple times.

In a later upgrade, the SF sets were no longer used to send D.C. pulsed digits, and were only used to transport on-hook/off-hook status; DTMF tones were then used to transport the dialed number information on Trunk Groups so equipped.

Modern signaling (SS7 or better) has certainly pushed all that old hardware into the scrap bin by now.

I could whistle off an SF set, but couldn't whistle fast enough to do digits.

I did get proficient at whistling 1000/20. That's 1 kHz modulated by 20 Hz. It was used on many "order wires."

Did you get any 416B tubes? They were a collectible from the old TD2 microwave gear.

Might have some of those upstairs in the attic. I do have some NOS Western

417A and 408A in cartons of 5 here in the shop. Also have a bunch of relays enclosed inside vacuum tubes. Looks like most are heated bimetal SPST. We loaded up a pickup with a 6 and 12 gig transmitter (if my memory is correct on the frequencies)a bunch of waveguide for both frequencies, large copper grounding strips with copper screws and a bunch of other things. We were like kids in a candy shop since the three of us who went were into tube gear big time.

Those clunky old keypress switches were not any faster than an ordinary rotary dial.

Around the same era, in the UK - as well as other aligned commonwealth countries - trunk dialling was carried out using the 2VF trunk dialling system and it was quite sophisticated. This audio demo

gives some idea of its operation. You will note that when the operator plugs into the outgoing trunk to establish the call a series of short "trunk pick-up" tones is issued, followed by 2VF dialled pulses generated by the operator rotary dial. At call termination a set of "clear-down" tone pulses is produced to release the trunk.

Clunky? Not really, at least not those used in the US. They were much faster than a rotary dial. I could punch out an entire number string in the time it would take a rotary dial to complete a zero. The Operator was finished and handling another call before the Sender's first digit was outpulsed.

That was pretty cool.

Telephone ads through the decades.

Three buddys of mine collect old, old Railroad things.One of them owns a lot of Insulators that are worth a lot of money, some of them are rare Insulators.One of them collects old, old Railroad Chinaware.Valuable stuff. cuhulin