The Telecom Digest for August 11, 2010
Volume 29 : Issue 217 : "text" Format
Messages in this Issue:
|Re: Do rate centers cross state lines?||(Steven)|
|Re: Do rate centers cross state lines?||(David Kaye)|
|Re: Model 15 RO Teletype available (OT)||(Robert Bonomi)|
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Date: Mon, 09 Aug 2010 17:07:25 -0700
From: Steven <firstname.lastname@example.org>
Subject: Re: Do rate centers cross state lines?
On 8/9/10 3:30 PM, Sam Spade wrote:
> On the other side of that coin Zerox had a major facility on the east
> side of Pasadena, California. The main building was in GTE terriotry,
> formerly CWT territory. GTE built a new C.O. close by hopping to get
> Zerox to buy their SxS "centrex" system. This was mid-1970s when Pacific
> Bell, that served most of Pasadena had cut over to 1ESS several office
> codes, which served a smaller part of Zerox's facility on the west side
> of the street across from the main building. Zerox subscribed to Pacific
> Bell Centrex, which terminated in the little building. Zerox then
> shipped it under the street in a cable vault used for lots of company
> stuff. GTE took Zerox before the California PUC and lost.
I remember that, I helped build the Hastings Ranch CO which was built
for Zerox Electrical Optical Systems, it was built to Zerox Specs and
paid for mostly by them. A few years after that Zerox close the rather
large office building and now it is a bunch of offices. That was a
really strange office and had a switch that I had never seen before,
isle after isle of Centrx switches. I spent almost a year on that
project. There were condos on the hill above the CO and one real nasty
old lady keep calling the police because as she put it, there was noise
24/7. GTE tried to settle with her, but in the end it went to court and
GTE took here down to her panties.
The only good spammer is a dead one!! Have you hunted one down today?
(c) 2010 I Kill Spammers, Inc. A Rot in Hell Co.
Date: Tue, 10 Aug 2010 21:58:43 GMT
From: email@example.com (David Kaye)
Subject: Re: Do rate centers cross state lines?
Mark J. Cuccia <firstname.lastname@example.org> wrote:
>While the Verdi CA side is served with dial-tone from the Verdi NV
>side, each side has its own unique state/area code based NPA-NXX code:
Gosh! How do you folks find out this stuff? I can't find anything like that.
Date: Tue, 10 Aug 2010 19:05:51 -0500
From: email@example.com (Robert Bonomi)
Subject: Re: Model 15 RO Teletype available (OT)
In article <firstname.lastname@example.org>,
Lisa or Jeff <email@example.com> wrote:
>> ***** Moderator's Note *****
>> I learned to type on a Model 19 Teletype connected to a Ham radio
>> transmitter at the M.I.T. radio club, W1MX, in the Sixties. The
>> machine required both a sense of timing and strong fingers: the
>> keyboard was locked during the time when the previous key-choice was
>> read by the mechanism, so producing consistently high speeds meant
>> synchronizing your typing speed with that of the machine, and it took
>> more force to start a key in motion than it did to complete the
>> trip: each green keycap had a spring under it to absorb the typist's
>> force as the key bottomed out.
>I believe that in the telegraph world almost all transmissions were
>prepared ahead of time off-line by pre-punching a paper tape, then
>transmitting the tape at full speed. This of course also allowed for
>editing and correcting of typos. Every description of machine usage
>refers to this practice.
Depends greatly on the application. And the 'urgency' of the message.
Wire-service "5 bells" stories were often typed 'live'. They were
too urgent for the latency of off-line composing.
On lightly-loaded remote circuit -- e.g. train orders on a low-traffic
section -- were also sometimes keyed live. There was 'bandwidth' to
spare, and it saved the time of the tape run, after the original keying.
When one wants to maximize throughput, and can tolerate the latency, off-
line prep is a necessity, Practically nobody can maintain even the 60/66
words/min of the medium-speed machines, with the uniformity of keystroke
spacing required. And, as line speeds got higher, it became more nearly
impossible for direct keying to keep the line busy.
>Some computer time shared systems used full duplex but there was a
>slight delay in the echo-back of the character. It was disconcerting
>to be typing and having the character print a moment after you tyed
An absolute non-issue with any 5-level TeleType(r) machine I ever
encountered. They were physically not capable of full duplex operation.
>Even the newer Teletype 33/35 keyboards were not easy to use. Some of
>the numeric shift characters did not match standard typewriters and
>the keyboard was 'heavy'.
Standard manual typewriter keyboards didn't match standard electric
ones either. Not to mention the fact that typewriter companies, like
IBM, Remington, etc. would sell you custom keytops with whatever
symbols you wanted on them. IIRC, IBM had well over 100
'off-the-shelf' substitute key-tops for he 'Model B' -- above and
beyond the 'standard' sets for any of the large number of languages
they sold, and would make 'anything" on special order.
>Anyway, I believe a company called "Black Box" made interfaces. I
>don't think a code conversion was necessary since the newer models
>33/35 TTY used ASCII. But your program had to shoot data out slowly.
The 33/35, and later ASCII models, had options for an RS-232 interface,
or current loop. The 33 could keep up with a 110 baud line, as long
as there were two 'null' characters after each [CR}. IT couldn't
get the printhead back to the left margin in 1/10 sec, 3/10 was adequate.
"Black Box Corporation', out of suburban Pittsburgh, was (and is) a
big player in providing 'glue' devices to allow incompatible devices
to inter-operate. Whether it was the physical layer, the data encoding
(character-set), or a higher-level protocol issue, they had solutions.
Their real forte was being able to turn out custom boxes for ANY
situation -- no matter whether you needed one device, or a thousand --
in short order (a 1- to 10-lot was typically under 2 weeks), and for
(all things considered) a very "reasonable" price.
***** Moderator's Note *****
Black Box has a very mixed reputation with me: I still have the RJ-48
jack that almost ended my engineering career, and Black Box sold it to
a contractor I hired. The contractor followed my wiring spec, and
connected the jack to a Cisco router, as part of a "media converter"
between "Type 1" and "Type 3" Token-Ring connectors, in a network I
built for a new control center that I was in charge of cutting over.
It didn't work, and I was informed of a failed test, with less than 24
hours to go before the cutover, with more than 1,000 technicians and
managers committed to work on a Sunday: I had to assemble a "Tiger
Team" and get them to the site on less than 24 hours notice.
We got the cutover to work, but the jack Black Box sold turned out to
have the colors wired backwards: pin 1 was Brown, pin 8 was
wh/blue. The contractor had wired it by color, which was what any
technician would do.
Once burned, twice careful: I never bought another part from Black
Box, and never allowed my contractors to do it either.
BTW, all Teletype machines I used for ham radio, i.e., Models 15 and
19, were capable of full duplex operation. They were wired for
half-duplex, but that wasn't a limit of the design.
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