Compu-Fix/Compu-Fix.iso/pubnews/td10464.txt

Text File | 1993-03-01 | 18KB | 306 lines

TELECOM Digest     Mon, 2 Jul 90 00:58:31 CDT    Volume 10 : Issue 464

Inside This Issue:                         Moderator: Patrick A. Townson

    Re: What Is Telex? Is There an E-Mail Interface? [Donald Kimberlin]
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Date: Sun, 1 Jul 90 22:56 EST
From: "Donald E. Kimberlin" <[e-mail]>
Subject: Re: What Is Telex? Is There an E-Mail Interface?
Organization: Telecommunications Network Architects, Safety Harbor, FL


In article (Digest V10, Iss 462), Allan Spiegel writes:

>From time to time an article will give someone's telex number.  What
>is this, how does it work and how do I use it?  Is there some magic
>e-mail address that I can send mail to that will turn it into a telex
>like I can do for fax numbers?  Thanks.  I prefer e-mail responses.

 ..and our Moderator provides a short summary. Here is mine,
attempting to flesh out the matter for better understanding ... and
hopefully, use, by this readership. In fact, this writing is
extemporaneous, so there are gaps some others may be able to fill:

        As our Moderator's response said, Telex certainly should be
called the original form of E-Mail. Far from "dead" on a global basis,
UN reports published in the "Brittanica Book of the Year" indicate
there are about three million Telex lines around the globe.  Contrary
to the impression international telephone people like to create,
direct, immediate access via Telex still exists to more of the world's
political entities than does telephone.  This has been the case for
many years. (Totalitarian governments must like Telex; they have been
known to shut down telephone service, but not Telex.  The suspected
reason: It can be monitored with hard copy easily, and has often been
done,too.  Of course, they themselves use it for military messages.)

        Telex sprang from the same source as the Volkswagon automo-
bile: The creative growth era of the early Third Reich. It was devised
as a means to distribute military command and control messages and
data in a time before we even had a structure for data processing
machinery.  What existed at that point in time was 45.5 bps Baudot
automatic telegraphy and dial-pulsing telephone exchanges.  The
original Telex was essentially (director-controlled; yes, the
Europeans were doing that then) rotary telephone switches modified to
carry DC telegraph lines, providing a switched service for
teletypewriters in the same way as was done for telephones.

        There was one major difference: Intercity transmission
facilites were expensive and in short supply, and one analog telephone
circuit between cities could carry 24 (and in some applications, 25)
telegraph channels bearing Telex.  The economics are obvious, and
probably are what keep Telex important in the Third World today.

        In that era of transparent analog transmission lines, Telex
was easily able to use telephone dial-pulsing on the local telegraph
loops followed by Baudot teletype for the messages ... and it did.
Hence, this form of Telex operation became known as "type A Telex
signaling." It is still used that way in many nations.  In those you
will see a teleprinter with a control box that has a telephone dial.
When Western Union decided it had should enter into Telex in the U.S.,
it adopted the original style and Type A signaling.  Similarly, many
other Europeans adopted Type A operations, among them the U.K., France
and Belgium as well as others.  Meantime, (I think it was L. M.
Ericsson leading the move for) others saw an opportunity to simply use
the numerics on the keyboard for call set-up, thus some nations
adopted what became known as "Type B" Telex.  By this time, the CCITT
had taken charge and was setting international agreements, one of
which was to set the speed of international Baudot circuits at 50
Baud, instead of 45.5. Some few nations were many years behind in
upspeeding. In this writer's experience, Cuba and Pakistan are
remembered as still running 45.5 Baud Telex trunks even into the
1970's.

        Telex grew around the world very rapidly ... long before
automatic telephony, again most likely due to its economics of channel
usage.  Considerable networks of Telex on HF (shortwave) radio to
then-remote areas of Africa, the Middle East and Asia were established
by the government-owned PTTs, operating non-stop with error-correcting,
retransmitting time division multiplexers per CCITT Recommendation
R.44 (so what's new about TDM ... Baudot built his first one in 1873,
three years _before_ Bell's telephone.  Check it out, unbelievers!),
with the common name "TOR" for "Telex Over Radio."  Readers who are
SWL's certainly hear of TOR, SITOR and Telex Mux on shortwave radio
today ... there's still plenty around and on the air.

        Also, the broad reach and universality of Telex around the
world lead to the CCITT establishing the global network of
International Telegram (commonly called Cablegram; RCA's product on
its original shortwave radio was the Radiogram) channels on a switched
network overlay of Telex called "Gentex."  That's right: Your
international cablegram goes on Telex, too.  It's simply Telex
channels dialed up permanently between telegram offices.  The beauty
is that of any switched service: Restoration in case of channel
failure is simply dialing up another call.

        The result of all this is that Telex was, and remains in many
nations, _the_ mediumn of communications for business and both civil
and military government use.  Airlines using the PARS (and
internationally IPARS) reservations systems still run Baudot code
today (although many lines have changed to high-speed modem traffic),
because their plain-language text transmissions use only 7.5 bits per
character, compared to the 11 bits of CCITT International Alphabet 5
(known as ASCII in colloqial North America).  The economics are
obvious.  In many nations, the total minutes of international Telex
still today exceeds that of international telephone traffic.  Business
uses Telex more than most Americans understand.  West Germany has had
more than 400,000 Telex lines for years, while the U.S. at its peak
could count only 345,000 Telex _and_ TWX subscribers.  Americans
simply grew up as sociological prisoners of "the phone," under a
hegemony that taught them anything else must be insignificant.

        Almost in parallel with the 1930's development of Telex, Bell
interests saw the possibilities and decided to do Telex one better.
Bell Labs was commissioned to develop a simialr service, using dial
pulse selection. It became known as Teletypewriter Exchange Service,
or TWX.  (In fact, Bell beat WUTCo to the marketplace punch and WUTCo
came along later with Telex in the U.S.)  The original TWX ran 75 bps
with Baudot code and dial selection, until Bell Labs got its second
generation ready. That one, called "four-row TWX" in telephone
parlance, used *modems* called "101 Data Sets" (that's right, Daddy of
the 103!) on two-wire ordinary telephone subscriber lines run to
special exchanges called a WADS (Wide Area Data Service) exchange in
each major city, where the billing and such was done.  Actually, a
WADS exchange was a partition of one local telephone exchange in the
city. Because it was using the Public Switched Telephone Network (DDD
in American parlance, TWX was given reserved area codes ... 510, 610,
710, 810 and 910.  Some few remote locations on TWX are still on those
area codes.

        Four-row TWX used 11-bit characters to provide an expanded
code set including "control characters" that permitted the TWX machine
to be operated much like an office typewriter ... more so than Telex
and its Baudot limitations that at best used CCITT-standardized
"character strings" to provide some degree of functionality beyond
plain text (see the CCITT F, R and S Series of Recommenda- tions). The
control characters of TWX provided paragraph indents, form feeds and
such that Telex never really had.  And, with Four-Row TWX,
transmission (on the 101 Data Set) was upped to 110 bps, and the code
provided VRC "parity" error-checking. (One can show that 110 bps with
11-bit characters is equivalent to about 140-150 words per minute, a
typing speed only Olympic-class typists could achieve on mechanical
typewriters.)  Even so, the "TWX code" had only 93 of its 128 possible
characters assigned.

        It just so happened that when the computer era came along,
Bell's Teletype Corporation (at Skokie, Il, purchased from Dr.
Kleinschmidt to get a supply of teleprinters for TWX) had its Model 33
teleprinter in production for TWX.  That was, in its time, the
cheapest keyboard instrument readily available for the then-"new"
computer business.  The Model 33 teleprinter and its mechanically-
embedded TWX code became the _de_facto_ I/O device for the computer.
The computer people early on wanted use of all the character
combinations in the code, so Teletype obliged with modifications for
computers.  Thus ASCII was born of TWX code, and it ultimately became
CCITT International Telegraph Alphabet Number 5.  The IA5 definitions
in the CCITT books vary from ASCII only in wording. Study of both
ASCII and IA5 can show roots of most of the character combinations
back to Baudot (or its CCITT character strings) and even manual
telegraphy.

However, computer programmers and computer mux makers who don't
understand this have often done some horrible things to uses of the
code, causing products that alienate people from data communications;
wondering why their products don't migrate well or why people have
trouble understanding them.  There is a certain beauty of human logic
in using these codes properly.  They grew out of manual operations in
sending messages.  One can even see in IBM's BCDIC and later EBCDIC an
emulation of what was in the telegraphic codes, but I doubt IBMer's
for their part would admit that.

        While Telex was the rest of the world, insular America grew
with its parallel Telex of WUTCo and TWX of Bell.  Because Bell was
strictly limited to dial telephony only for international business,
and because WUTCo had given up its international operations in a 1939
deal to monopolize domestic telegraph business by taking over ITT's
Postal Telegraph (which was a thorn in WUTCo's side), the U.S.
developed a unique sort of "international telegraph" company known as
an "International Record Carrier." The IRC's were an interesting
catch-all sort of firm; an American answer to "how do we get a regu-
latory handle on all these characters?"  Some were US-based, like
WUTCo's "Cable System" that became Western Union International when
sold off as a result of the 1939 Postal Telegraph deal.  Others had
"just been there," like ITT's World Communications that had been a
gaggle of companies with names like Federal Telegraph, All American
Cables and Radio, Globe Wireless, Press Wireless, and the common
carrier part of Mackay Marine.  RCA Communications had been around
specializing largely in spanning the Pacific with radio as well as
generally reaching ships and other places by radio telegraphy; today
it is the RCA Globecom subsidiary of MCI (as is WUI, calling itself
MCI International).  Tropical Radiotelegraph grew out of putting radio
telegraph on shipboard before WWI so its owners, the United Fruit
Company of Boston could divert shiploads of bananas to the best market,
expanding to communications to its plantations, then becoming in
some nations the public telegraph and international telephone company
of the nation; today it is TRT Telecommunications.  The French
Telegraph Cable Company, owned by French investors in the PTT had been
in the U.S. since the days of Monsier Puyer-Quartier laying telegraph
cables from France to the U.S., hence its telegraphic routing address,
PQ. Even the Firestone Tire & Rubber Company owned its own IRD, the
Trans-Liberia Radiotelegraph Company, operating HF radio from Akron to
its rubber plantations in Liberia.  (TL is still there in Akron, as a
matter of fact.)

        All these firms formed the U.S. IRC business and enjoyed a
period of regulated competitiveness for thirty years or so. They were the
Telex interface between the U.S. and the world, all connecting out to
WUTCo Telex and (by performing "protocol conversion" long before
computers did so,) Bell TWX.  International Telex users were
confronted with some typical American confusion ... they had to prefix
their Telex calls to America with added digits to steer their call via
the IRC of their choice (in most nations) and then to either Telex or
TWX for the U.S. domestic connection.

        All that had to change when Congress "deregulated" the IRC's
in 1982, four years before telephony had a similar change.  Restric-
tions on AT&T providing only telephony were lifted; the IRC's were
freed to operate anyplace as compared to a limited number of "gateway
cities," WUTCo was permitted to go international once again, and
everybody could compete for any kind of business.

        That's what has happened in America, so you can call FTCC
(formerly French Cable) as well as relative newcomers to the U.S.
market like Cable & Wireless (from the U.K.) and ask them what deal
they will offer in competition to AT&T or WUTCo, either domestically
or internationally, for voice, data or video.

        International Telex remains a basic business.  The various
companies made various deals to interface to their Telex connections.
MCI's is, of course, via WUI, the first IRC that MCI bought.
AT&TMail's is via TRT. Along the evolutionary course of the later days
of the IRC business, a firm was established called Graphic Scanning
(IRC's have always tried to do something with facsimile, long before
Group III machines made them the Office Toy of 1990, and Graphic
Scanning got into the IRC field in this way), and Graphnet is
Telenet's Telex connection.

        As our moderator said, the E-Mail services all "alias" your
E-Mail address to their IRC connection.  It's usually your numeric
E-Mail address with a fixed prefix.  Example: My own AT&TMail numeric
is 7281481. Its Telex alias is 157281481. On MCIMail, my numeric is
4133373,and its Telex alias is 650-4133373.

        The global Telex network has had since inception a handy
"confirmation' convention called "Who Are You?" and each Telex machine
is encoded with an "automatic answerback" that lets you know on
connection and whenever you ask (WRU in Baudot; <ctrl-E> in ASCII)
what machine you are connected to.  So, if you are an E-Mail user,
your overseas correspondent will want to know your "network"and
"answerback."  That's usually the Telex code for the IRC you're with
and your E-Mail aplha address.  So, mine on MCIMail is MCI UW
dkimberlin and on AT&TMail mine is TRT UT dkimberlin.  Really rather
simple, when you understand the meaning and purpose of the IRC and
international Telex.

        One last word for this top-level exposition: Telex isn't so
cheap compared to E-Mail.  If you have a regular correspondent in
another nation and want to DDD to batch files, or if you have an X.25
or Teletex route to another nation (WUTCo's Easylink E-Mail does, but
the other E-Mails seem to say,"huh? Teletex?"), that may well be
cheaper than Telex.  It runs at 50 bps, just 66 words per minute, and
you get billed at the Telex output rate.

        All that said, then why bother? Well, Telex is still there and
readily accessible from your E-Mail, and it reaches those 3-1/2
million or so machines in offices of foreign nations you may have only
occasional traffic for. And, those machines are in global directories
like the Jaeger u. Waldmann directories so you can look them up from
home. And, those machines are in hotels all around the world, so you
can get a message to the traveler who hasn't been able to get a phone
line out for three days.  And, those Telex lines connect to all the
cablegram offices that will for their high price, still send a
messenger to _find_ your missing salesman (unlike the US' rapidly
deteriorating telegram service).  As well, they reach the ships at sea
with your Telex to roust up the staffer who's on an ocean cruise.  No
matter where in the world they are; no matter what time zone they are
in, no matter if they are on the Gregorian or Moslem or Hindu or
Bhuddist calendar, your message routed by Telex should get to them far
more efficiently than random dialing of the phone.

        So, while most Americans discovered some of these advantages
when the Group III fax came along, but still need to find a "fax
number" that's not in a directory like Jaeger u. Waldmann, your E-Mail
connection to international Telex is a potentially useful tool.

        (For those who may want a fuller, more detailed explanation,
Datapro Research offers reprints of a 22-page 1986 report they had me
author, numbered MT20-510-101, by calling [phone].  Readers who
have Datapro's "Nanagement of Telecommunications" service may have
this at hand.)

A final riposte: Our Moderator said in commenting to the question:

>In case you were wondering, FAX is the (FA)csimile E(X)change.

Au contraire, notre cher moduerateur.  While some marketeers of recent
facsimile service offerings may have made that linkage, the term "fax"
has been used generically by the much more limited group of facsimile
(including telephoto) users from telecomm time immemorial.

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End of TELECOM Digest V10 #464
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