[GreenKeys] Old stories of Teletype and Data Communications...
k9tty at dls.net
k9tty at dls.net
Fri May 9 22:58:47 EDT 2008
Thanks for sharing Michael,
Those older DATA-PHONES and DATA-SETS were state of the art analog technology from approximately 1953 to 1973.
I installed two experimental dataphones. Each was accompanied by an engineer from Bell Labs.
The first one was small and known as the X-401E. It used a set of parallel tones to act as telemetry for a power company substation.
I kept getting called out when the telemetry failed. I noticed that every time it rained the modem failed. HMMMMM
So I asked the chief tester to have someone from construction to check the cable entrance for the substation.
Gophers had eaten right through the lead casing exposing the copper conductors just enough so that they shorted only when it rained.
The other experimental set was huge. It was the X-203. An analog modem that had a data rate switch. Depending on the private line circuit it was
connected to, and the like set at the other end, it would send and receive 19.2 kilobits per second in full duplex. If too many errors occurred you
selected 9600 baud. In addition to the modem which was about the size of a two drawer filing cabinet, it came with a look alike module of the same
size, which was the error control unit. It took four of us to move the darn thing. I installed it in Mt. Prospect, Illinois at Addressograph Multigraph Corp.
They used it to send high resolution facsimiles of their manufacturing blue-prints. The darn thing actually worked at 19.2 kb without a single case of
trouble. Mind you that this was 1970. In 1970 2400 baud was considered fast and 4800 was very fast.
The 203A (dialup) and 203B (private line) actually made it into production at about half the size and weight, only requiring one man with a hand truck.
But it did not last long as DataPhone Digital Service (DDS) made its entrance in 1977 making analog technology old fashioned.
I also remember the toll technician in the Libertyville, Illinois Central Office telling me that "This digital carrier (T1) is a poor substitute for analog
frequency division multiplex systems, and it will never last!"
I should also write about my experiences with Type 4 Dataspeed with error detection and correction. A real blaster of a reader and punch that would
operate at 2400 baud in school and 2000 in the field. I wish I had taken a movie of the system. You would have a hard time running to keep up with the
punch. Then watch with amazement when an error was introduced. The reader would back the tape up and so would the punch, then the punch would
over punch all of the errored word and start the reader again to re-punch the word.
And then there was the Dataspeed printer aka Inktronic. It could print at 2400 baud by spraying ink through a set of gates that formed all 40 characters
across the page at the same time. The inkjets were so powerful you could sent the purple ink across the room. It also had the weirdest circuit boards I
have ever seen. Shaped like the letter U.
At the same time of these technical marvels we were still maintaining 600 Teletype machines, analog carrier transporting telegraph circuits (43A) and the
test center was testing data-phones across the USA and Canada.
I guess I should write a collection of short stories some day before I go to that data test center in the sky...
Old Don
Tracer of open circuits and lost causes...
K9TTY
On Fri 9/05/08 1:13 PM , Michael O'Day odaymg at yahoo.com sent:
> Hi Don,
>
> Likewise, yours were great stories. I came into the
> datacomm arena a little later that you (1980) with
> Burroughs Corp in Chicago. I used to maintain several
> sites (banks and one railroad)which were "on-line" via
> dedicated sync/async phone lines and modems that ran
> at 700, 1200 or 1800 baud. Our boss got a call one day
> from the railroad complaining that one of his
> operators was picking up the modem (about the size of
> a shoebox) and was repeatedly droping in on the desk
> to make it work because that was what the night
> operator had told him to do. Turned out the FE on call
> was familiar with the ongoing problem with one
> circuit, and had asked the night op to pick up one end
> of the modem about an inch and drop it to reseat the
> boards inside (which worked, a common problem). So the
> operator put up a note advising the day shift to "drop
> the modem onto the desktop in case of problem". Since
> he didn't specify a distance, the day op was bouncing
> it from about 2 feet up. Needless to say, the modem in
> Baltimore was replaces post haste.
>
> Mike - N9ODM
>
>
> --- Don Robert House k9tty at dls.net> wrote:
> > Hi Wallace,
> >
> > Nice story. Thanks for sharing...
> >
> > I remember the electrowriters! I also remember
> the> TWX at
> > Hallicrafters that was attached to dial tone
> through> a steel box with
> > an interface to a KW-7 crypto unit. They
> kept> telling me that the 28
> > ASR would not send. Two times I proved that
> the> KW-7 was not giving
> > the tD a ground. They still did not believe me so
> I> had two of them
> > "watch carefully" while I put a screwdriver on
> the> battery lead and
> > let the shaft touch the frame... BIG SPARK and
> the> reader started.
> > One of them fell back on his buttocks. I never
> had> to go back there
> > again. Tee hee.
> >
> > Don
> >
> >
> > On 8 May 2008, at 2:51 PM, MURRAY, WALLACE W
> > (ATTASIAIT) wrote:
> >
> > Great Story Don.
> >
> > Similar stories come out of the Ford Rouge plant.
> > In the old days,
> > the telephone company really did nothing inside
> the> plant. The
> > telephone company pulled up to the gate handed
> the> electricians at
> > Ford's the cable and phones and Ford
> electricians> did the rest. Old
> > man Henry Ford cut a deal with the president
> of> Michigan Bell. This
> > arrangement did not change until registration
> and> divestiture, when
> > the telephone company said we would meet them in
> the> telephone room in
> > one building. Very quickly, separate conduit
> runs> and manholes were
> > established just for telephone cables.
> >
> > Ford tended to run everything in the same
> conduit> runs. So you could
> > go into one of their manholes and find 130
> KV> electric power, high
> > pressure super heated steam, and steam rated
> > telephone cables. Well,
> > as you might expect, every now and then they had
> a> power fault causing
> > the manhole to explode. It literally
> destroyed> everything in the
> > manhole and often shot the manhole frame and
> cover> one hundred feet in
> > the air.
> >
> > Not sure if I ever told you about the
> teletype> machines installed at
> > Great Lakes steel on the hot strip mill.
> >
> > Anyway, they were having an electrowriter
> problem> which was traced to
> > our local building cables. As the young grunt,
> who> was expected to
> > drive the car, get coffee and then find the
> problem,> I went along in
> > search of the bad cable. Not sure if you ever
> were> in a hot strip
> > rolling mill, but at the end of the line there is
> a> large area where
> > they let the steel that gets out of control pile
> up.> This is also the
> > point where they needed a model 28 RO so they
> could> identify the coil
> > of steel they just made. Everything worked
> fine> until the first time
> > the steel being rolled started to dance and
> jumped> off the strip
> > mill. You guessed it, it piled up right into the
> 28> RO going about 40
> > miles an hour. The TTY wound up being about
> one> inch thick. After
> > one or two more failures, the folks at the mill
> put> their heads
> > together and made this shroud out of one inch
> thick> steel plate.
> > There was a hole in it just big enough so you
> could> reach in and tear
> > off the copy on the TTY.
> >
> > I of course was very interested in the
> arrangement> and asked them how
> > they serviced the machine or even changed paper.
> > They pointed out the
> > big lifting ring on the top of the shroud and
> the> overhead crane.
> > When service was needed, the crane operator
> lifted> the shroud off,
> > work was performed and the shroud replaced.
> More> important, every one
> > was happy.
> >
> > From: Don Robert House [k9tty at dls.net]> Sent: Wednesday, May 07, 2008 7:11 PM
> > To: MURRAY, WALLACE W (ATTASIAIT)
> > Subject: Re: India's communications
> >
> > This wiring mess reminds me of the (lack of)
> the> wiring plan at the
> > Motorola Tube Plant in Franklin Park, Illinois.
> We> could not get the
> > covers on the cross-connect boxes. Motorola
> wanted> each and every new
> > kind of circuit and service we could provide
> them> from data
> > communications, to Teletype, to
> picture-phone> intercom service. But
> > they would never let us take any service out
> and> would never let us do
> > any clean up of the wiring. Motorola's 756
> PBX> rivaled some
> > villages and towns' central offices. They had
> Chief> Operators for the
> > PBX and for the Teletype pool. They even had
> an> Executive Operator
> > and Traffic Manager. Those were the days
> our> foreman had to come out
> > and stop the fighting between the different
> > departments for our repair
> > and installation priorities. Things changed 200
> %> when Panasonic took
> > over the plant. Almost everything was
> removed.>
> > Memories, some of the good old days were not
> so> good.
> >
> > Don
> >
> > Former Teltype repairman, data communication
> > serviceman, SSB Circuit
> > Designer, CPC trainer, Transmission
> Engineer,> Regional transmission
> > product selection manager
> > Now suffering retiree and tax payer... Where
> did> all those benefits
> > go anyway?
> >
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