Telegraphy





Telegraphy is the long distance transmission of written messages without
physical transport of letters. This definition includes recent forms of data
transmission such as fax, email, and computer networks in general. (A
telegraph is a machine for transmitting and receiving messages over long
distances, i.e. for telegraphy.)

   * Before the internet came into general use, telegraphy messages were
     known as telegrams or cablegrams, often shortened to a cable or a wire
     message. Telegrams sent by the Telex network, a switched network of
     teleprinters similar to the telephone network, were known as a telex
     message. Before long distance telephone services were readily
     available, telegram services were very popular. Telegrams were often
     used to confirm business dealings and, unlike e-mail, telegrams were
     commonly used to create binding legal document for business dealings.

   * Before fax machines came into general use, wire picture or wire photo
     was a newspaper picture that was sent from a remote location by a
     facsimile telegraph. This is why many fax machines have a photo option
     even today.

The first telegraphs were optical, including the use of smoke signals and
beacons. These have existed since ancient times. A semaphore network
invented by Claude Chappe operated in France from 1792 through 1846. It
helped Napoleon enough that it was widely imitated in Europe and the U.S.
The last (Swedish) commercial semaphore link left operation in 1880.

Semaphores are faster than smoke signals and beacons and consume no fuel.
They are hundreds of times as fast as post riders and serve entire regions.
However they require operators and towers every 30 km (20 mi), and only send
about two words per minute. This causes them to have a cost per word-mile
roughly thirty times as high as electric telegraphs. This is useful to
government, but too expensive for most commercial uses other than commodity
price information.

The first commercial electrical telegraph constructed by Sir Charles
Wheatstone entered use in London in 1838. An electrical telegraph was
US-patented in 1842 by Samuel Morse, who also developed the Morse code
signalling alphabet, and was quickly deployed in the following two decades.
Nikola Tesla and other scientists and inventors showed the usefulness of
wireless telegraphy, or radio, beginning in the 1860s.

A continuing goal in telegraphy has been to reduce the cost per message by
reducing hand-work, or increasing the sending rate. There were many
experiments with moving pointers, and various electrical encodings. However,
most systems were too complicated and unreliable.

With the invention of the teletypewriter, telegraphic encoding became fully
automated. Early teletypewriters used Baudot code, a 5-bit code. This
yielded only thirty two codes, so it was over-defined into two "shifts,"
"letters" and "figures." An explicit, unshared shift code prefaced each set
of letters and figures.

A standard timing system developed for telecommunications. The "space" state
was defined as the powered state of the wire. In this way, it was
immediately apparent when the line itself failed. The characters were sent
by first sending a "start bit" that pulled the line to the unpowered "mark
state." The start bit triggered a wheeled commutator run by a motor with a
precise speed (later, digital electronics). The commutator distributed the
bits from the line to a series of relays that would "capture" the bits. A
"stop bit" was then sent at the powered "space state" to assure that the
commutator would have time to stop, and be ready for the next character. The
stop bit triggered the printing mechanism. Often, two stop bits were sent to
give the mechanism time to finish and stop vibrating.

The transatlantic telegraph cable was then successfully completed on July
27, 1866 which for the first time allowed transatlantic telegraph
communications. Another advance occurred on August 9, 1892, when Thomas
Edison received a patent for a two-way telegraph.

By 1935 message routing was the last great barrier to full automation. Large
telegraphy providers began to develop systems that used telephone-like
rotary dialing to connect teletypes. These machines were called "telex."
Telex machines first performed rotary-telephone-style pulse dialing, and
then sent baudot code. This "type A" telex routing functionally automated
message routing.

The Third Reich invented the first wide-coverage telex system, and used it
to coordinate their bureaucracy. It was a true triumph of German efficiency.

At the then-blinding rate of 45.5 bits per second, up to 25 telex channels
could share a single long-distance telephone channel, making telex the least
expensive method of performing reliable long-distance communication.

As of 1970 Cuba and Pakistan were still running 45.5 baud type A telex.
Telex is still widely used in third-world bureaucracies, probably because of
its low costs. The U.N. asserts that more political entities are reliably
available by telex than by any other single method.

When dictatorships cut off telephone, fax and internet service, their telex
networks remain up. A major advantage for dictatorships is that telex
networks are easy to tap: Taps automatically generate complete transcripts.

Around 1960[?], some nations began to use the "figures" baudot codes to
perform "Type B" telex routing.

Telex grew around the world very rapidly. Long before automatic telephony
was available, most countries, even in central Africa and Asia, had at least
a few high-frequency (shortwave) telex links. Often these radio links were
the first established by government postal and telegraph services (PTTs).
The most common radio standard, CCITT R.44 had error-corrected
retransmitting time-division multiplexing of radio channels. Most
impoverished PTTs operated their telex-on-radio (TOR) channels non-stop, to
get the maximum value from them.

The cost of telex on radio (TOR) equipment has continued to fall. Many
amateur radio operators currently (2002) operate TOR with special softare
and inexpensive adapters from computer sound cards to shortwave radios.

Modern "cablegrams" or "telegrams" actually operate over dedicated telex
networks, using TOR whenever required.

PARS and IPARS (the airline reservation systems) still (2002) use Baudot
code, because it requires only 7.5 bits per character. A bit saved is a
penny earned.

In Germany alone, more than 400,000 telex lines remain in daily operation.
Over most of the world, more than three million telex lines remain in use.

Almost in parallel with Germany's telex system, Bell Labs in the 1930s
decided to go telex one better, and began developing a similar service (with
pulse dialing and all!) called "Teletype Wide-area eXchange" (TWX).

TWX originally ran 75 bits per second, sending Baudot code and dial
selection. However, Bell developed a second generation of "four row" modems
called the "Bell 101 dataset," which is the direct ancestor of the Bell 103
that launched computer time-sharing. The 101 was revolutionary because it
ran on ordinary subscriber lines that could (at the office) be routed to
special exchanges called "wide-area data service." Because it was using the
public switched telephone network, TWX had special area codes: 510, 610,
710, 810 and 910, some of which remain in use.

The "four row" TWX service had "control characters" that let the machine
behave like office typewriters. These provided paragraph indentation, form
feeds, and other services that were never available with Baudot codes.
However, the TWX code only used 93 of 128 characters.

The Teletype corporation was founded by a Dr. Kleinschmidt. It had the
cheapest teletypewriters that could be adapted to the TWX code. Bell
purchased the corporation to assure its supply of "model 33" TWX
teletypewriters.

The model 33 was the cheapest teletypewriter available for use with
computers. Computer people of course wanted a full set of characters.
Teletype provided them.

ASCII was born from TWX code. It was formalized as CCITT international
alphabet 5. Careful study will show that ASCII traces many character codes
back to Baudot, which in turn traces some characters back to manual
telegraphy.

Bell's original consent agreement limited it to international dial
telephony. WUTCo (Western Union Telegraph Company) had given up its
international telegraphic operation in a 1939 bid to monopolize U.S.
telegraphy by taking over ITT's PTT business. The result was deemphasis on
telex in the U.S. and a cat's cradle of small U.S. international telex and
telegraphy companies. These were known by regulatory agencies as
"International Record Carriers"

   * Western Union Telegraph Company developed a spinoff called "Cable
     System." Cable system later became Western Union International.
   * ITT's "World Communications" was amalgamated from many smaller
     companies: "Federal Telegraph," "All American Cables and Radio," "Globe
     Wireless," and a common carrier division of Mackay Marine.
   * RCA communications had specialised in crossing the Pacific. It later
     joined with Western Union International to become MCI.
   * Before World War I, Tropical Radiotelegraph put radio telegraphs on
     ships for its owner, The United Fruit Company, in order to deliver
     bannanas to the best-paying markets. Communications expanded to UFC's
     plantations, and were eventually provided to local governments. TRT
     Telecommunications (as it is now known) eventually became the national
     PTT of many small nations.
   * The French Telegraph Cable Company (owned by French investors) had
     always been in the U.S. It laid cable from the U.S. to France. It was
     formed by "Monsieur Puyer-Quartier." This is how it got its telegraphic
     routing ID "PQ."
   * Firestone Rubber developed its own IRC, the "Trans-Liberia
     Radiotelegraph Company." It operated shortwave from Akron OH to the
     rubber plantations in Liberia. TL is still based in Akron.

Bell telex users had to select which IRC to use, and then append the
necessary routing digits. The IRCs converted between TWX and Western Union
Telegraph Co. standards.

Around 1965, in a near-psychotic break with existing standards, DARPA
commissioned a study of decentralized switching systems, hoping to find
something more advanced than TOR that could still hope to survive a nuclear
war. The contractors developed the internet.

The internet was a radical break in three ways. First, it was designed to
operate over any media. Second, routing was decentralized. Third, large
messages were broken into fixed size packets, and then reassembled at the
destination. All previous networks had used controlled media, centralized
routers and dedicated connections.

The internet was designed with nearly grotesque economies. It is commonplace
for internet packets to use less than 1% of their bits for overhead. This
cheapness combines synergistically with the internet's ability to live on
other media. A typical cycle occurs when the internet encounters another
network, like telex, fidonet, ATM, or (as we are seeing with cable-modem
based internet phones) the public switched telephone network:

   * First, internet protocols are tunneled through the other network, as a
     convenience, usually for some specialized or office application.
   * Second, users come to expect the reliable global interconnectivity of
     the Internet, often for e-mail, or nowadays, for web access. Just
     because it's old and well debugged, the internet can seduce a user with
     a young, poorly behaved proprietary network.
   * Third, native applications of the competing network are deprecated,
     often because "nonproprietary" internet versions of similar services
     become available.
   * Fourth, an alternative cheaper or higher-speed internet-compatible
     medium becomes available, and the organization begins to install it.
   * Fifth, the proprietary network is rationalized out of existence as a
     cost-cutting maneuver, often because the internet protocols have such
     low percentages of overhead (i.e. wasted) data.

Around this time, T-1 "synchronous" networks became commonplace in the U.S.
A T-1 line has a "frame" of 24 bits that repeats 64000 times per second. The
first bit, calle the "sync" bit, was used to find the start of the frame. It
alternates between 1 and 0. Customarily, a T-1 link is sent over a balanced
twisted pair, isolated with transformers to prevent current flow. Each bit
of a frame is usually used to send a single voice or data channel. The
Europeans began to use a similar system (E-1) that sent bits as "octets" of
eight related bits.

In 1982, the U.S. Congress deregulated the IRCs. They began combining to get
economies of scale. All of their descendants offer voice, video and data
services.

In 1992, computer access via modem combined with cheap computers, and
graphic point & click interfaces to give a radical alternative to
conventional telex systems: personal e-mail.

E-mail was first invented for Multics in the late 1960s. However it was
limited to a single computer until the internet connected them around 1968.
Various private networks (UUNET, the Well, GENIE, DECNET) had e-mail from
the 1970s, but subscriptions were quite expensive for an individual- $25 to
$50 a month, just for e-mail. Internet use was then pretty much limited to
government, academia and other government contractors until the net was
opened to commercial use around 1989[?]. Individual e-mail accounts were not
widely available until local ISPs were in place, funded by people's desire
for web access. This was about 1992.

By using the time-shared systems almost end-to-end, the cost of data
communications plummeted to less than 10 cents a message.

International Telex remains available via E-mail ports. It is one's e-mail
address with numeric or alpha prefixes specifying one's IRC and account.

Telex has always had a feature called "answerback", that asks a remote
machine to send its address. If using telex via e-mail, this address is what
a remote telex user will want in order to contact an e-mail user.

This is how smoke-signals became modern digital telecommunications.