Anyone remembers the 'Telex' ?

Thread Starter

Externet

Joined Nov 29, 2005
1,818
Greetings.
I believe the correct word is 'teletype' , Telex a brand...
I never had the opportunity to disembowel nor learn much details of its inner workings. They were not cheap nor found as dumpster candidates. Few business offices had them. Have a faint recall about them.
As transmitting, I suppose it was just as a telephone for dialing; then choose typing or feeding the perforated paper tape, (that by the way I was able to read ! Not fast, but able). I do not know if there was an acknowledgment protocol after dialing.
As receiving; the thing was able to work unattended; when a call was received, -never heard a 'ring'- went 'off-hook' by itself, started typing and went on-hook at the reception of some other ending protocol ?
Had a telephone pair from telco and 120VAC plug. I think.

Suppose there is some operation general description somewhere on the web; but, what do you know about them ? Just nostalgic.

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AlbertHall

Joined Jun 4, 2014
11,959
When I was at school we wrote programs onto paper tape (in pascal if memory serves), the tape was posted to the education HQ and they ran it on their computer and then posted the resulting tape back. It made for a very long debug cycle!
 

ErnieM

Joined Apr 24, 2011
8,273
Well, since these things go back over a hundred years...

I used one in the 70's as the primary means of interacting with a PDP-8L computer. What you typed appeared on the printer, and you could also engage the paper tape punch to make a handy reference copy, say after you typed in a program and then typed L-I-S-T.

Teleprinter From Wikipedia, the free encyclopedia
 

ErnieM

Joined Apr 24, 2011
8,273
When I was at school we wrote programs onto paper tape (in pascal if memory serves), the tape was posted to the education HQ and they ran it on their computer and then posted the resulting tape back. It made for a very long debug cycle!
Yikes! Our computer was in the same room, running four terminals, two over phone lines to other schools with "acoustic" modems, literally boxes with a speaker and a mic you would insert a phone handset into.

Once or twice a day an other school would call to request a reset, which was literally banging the hand set into your palm to get the carbon bits in the mic to mix up.
 

Thread Starter

Externet

Joined Nov 29, 2005
1,818
In the early 90's, I rescued 3 or 4 discarded units, but those used thermal printer heads, very quiet and modern, like slim typewriters with not much mechanisms. Lots of high precision resistors in their modem boards, canibalized many components from them. Never played connecting them to a compfuser. :(


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nsaspook

Joined Aug 27, 2009
9,466
I repaired and used the old 60mA current loop Baudot code teletype machines that were usually connected to cryptographic machines. We had scores of teletype circuits connected by computer, hard-wire, HF FSK or audio interface Satcomm links..

radioman-2nd-class-lindely-repairs-a-teletype-machine-in-the-maintenance-department-67891b.jpgradioman-3rd-class-linda-andrashko-reviews-a-teletype-message-being-received-a89de4.jpg

A typical UYK-20 teletype system. The main console and interface TTY was 8-bit ASCII but most of the message outputs were 5-bit Baudot to 60mA loop teletype machines.
http://www.bitsavers.org/pdf/univac/military/an_uyk-20/UYK_20_20A_Technical_Summary_May91.pdf
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NAVMACS automated message on USS Missouri.

http://www.kh6bb.org/photos1.html
 
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Delta Prime

Joined Nov 15, 2019
1,326
For my high school science fair I chose the chronological history of electronic communications.In my research,this sentence "The quick brown fox jumps over the lazy dog," stuck with me because it uses every letter in the alphabet, to check the codec error rate. (Developed by Western Union to Test telex/two-way text communications).
 

SamR

Joined Mar 19, 2019
4,127
Yup I rescued a Telex with the idea of using it for HAM RTTY but was one of those projects that never actually launched. Was being sent to the dumpster by our purchasing department when I grabbed it. Sat on the shelf for many years before it finally made it to the dump. There was also TelAutograph which was sort of the analog version of Telex and precursor for FAX machines. Desktop computers quickly made them obsolete. The quick brown fox was taught in every typing class back when and probably predated Telex.
 

MrChips

Joined Oct 2, 2009
25,928
My first contact with a mainframe computer was with a CDC 6400. While we never got close up to it, our only contact was feeding decks of computer cards to the operator's window and receiving huge wide paper printouts two hours later in the output room. We were given only so many tickets per course to limit how many jobs you could run. When we ran out of tickets we had to beg the instructor for more tickets.

Then for my 4th year university computer course we got hands-on play with a DEC PDP-8/S with a Teletype ASR 33 machine which always needed servicing. There was only one computer and one terminal for an entire class of about 30 students. The following year I was given the responsibility of running the computer lab and one of my many tasks was keeping the ASR 33 functional. The toughest job was getting the mechanism to align correctly with 4-20mA current loop at 110 baud. For this I had to use a stroboscope in order to watch the pawls and levers do their right thing at the right moment.

I know a colleague who has saved an ASR 33 from the scrap yard.

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MrChips

Joined Oct 2, 2009
25,928
Years later Teletype upgraded the teletype writer with the Model 43 Teleprinter.
This was a huge improvement. The funny thing about it was they retained the old mechanical bell.

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SamR

Joined Mar 19, 2019
4,127
Yup the model 43 looks like the one I had. Extremely well-made heavy-duty keyboard on that thing. Wasn't much bigger than an IBM Selectric typewriter.
 

MaxHeadRoom

Joined Jul 18, 2013
25,010
I have used one to reload a PDP8 CNC machine, prior to that I used one in HM forces together with morse Transmission and paper punch.
I converted the PDP8 to RS232.! :p

.
 

Reloadron

Joined Jan 15, 2015
6,532
My memories were early and mid '60s and pretty much RTTY (Radio Tele TYpe). Anyone working the ham radio bands as a kid heard those RTTY signals. For those who may still have a short wave receiver, I have an old R392 GI unit, you can pipe your audio into a sound card on your PC and there is some free software out there to decode RTTY. After all these years it's still out there. :)

Ron
 

MaxHeadRoom

Joined Jul 18, 2013
25,010
I remember typing up the tape in Libya to send the RTTY transmission anouncing the find of the US bomber 'Lady be Good' found by the exploration team from British Petroleum on November 9, 1958.
 

schmitt trigger

Joined Jul 12, 2010
496
My first job was for an Eastman Kodak subsidiary.
The purchase orders for chemicals and film went to the corporate offices in Rochester, NY. Those went through -you guessed right, a Telex machine.
The Telex operator was a very beautiful young woman with a quick smile and very sweet manners.
So whenever I went to the Telex machine I was, hmmm, hmmm, distracted, and never paid too much attention to it, other than the racket it made.
 
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