Telephone history

In 1830 the great American scientist Professor Joseph Henry transmitted the

first practical electrical signal. A short time before Henry had invented

the first efficient electromagnet. He also concluded similar thoughts about

induction before Faraday but he didn’t publish them first. Henry’s place in

electrical history however, has always been secure, in particular for

showing that electromagnetism could do more than create current or pick up

heavy weights — it could communicate.

In a stunning demonstration in his Albany Academy classroom, Henry created

the forerunner of the telegraph. IIn the demonstration, Henry first built an

electromagnet by winding an iron bar with several feet of wire. A pivot

mounted steel bar sat next to the magnet. A bell, in turn, stood next to

the bar. From the electromagnet Henry strung a mile of wire around the

inside of the classroom. He completed the circuit by connecting the ends of

the wires at a battery. Guess what happened? The steel bar swung toward the

magnet, of course, striking the bell at the same time. Breaking tthe

connection released the bar and it was free to strike again. And while

Henry did not pursue electrical signaling, he did help someone who did. And

that man was Samuel Finley Breese Morse.

For more information on Joseph Henry, visit the Joseph Henry PPapers Project

at:

http://www.si.edu/archives/ihd/jhp/papers00.htm (external link)

From the December, 1963 American Heritage magazine, „a sketch of Henry’s

primitive telegraph, a dozen years before Morse, reveals the essential

components: an electromagnet activated by a distant battery, and a pivoted

iron bar that moves to ring a bell.“ See the two books listed to the left

for more information.

In 1837 Samuel Morse invented the first workable telegraph, applied for its

patent in 1838, an

d was finally granted it in 1848. Joseph Henry helped Morse build a

telegraph relay or repeater that allowed long distance operation. The

telegraph later helped unite the country and eventually the world. Not a

professional inventor, Morse was nevertheless captivated by electrical

experiments. In 1832 he heard of Faraday’s recently published work on

inductance, and was given an electromagnet at the ssame time to ponder over.

An idea came to him and Morse quickly worked out details for his telegraph.

As depicted below, his system used a key (a switch) to make or break the

electrical circuit, a battery to produce power, a single line joining one

telegraph station to another and an electromagnetic receiver or sounder

that upon being turned on and off, produced a clicking noise. He completed

the package by devising the Morse code system of dots and dashes. A quick

key tap broke the ccircuit momentarily, transmitting a short pulse to a

distant sounder, interpreted by an operator as a dot. A more lengthy break

produced a dash.

Telegraphy became big business

as it replaced messengers, the Pony Express, clipper ships and every other

slow paced means of communicating. The fact that service was limited to

Western Union offices or large firms seemed hardly a problem. After all,

communicating over long distances instantly was otherwise impossible. Yet

as the telegraph was perfected, man’s thoughts turned to speech over a

wire.

[pic]

Bell continued harmonic telegraph work through the fall of 1874. He wasn’t

making much progress but his tinkering gathered attention. Gardiner Greene

Hubbard, a prominent Boston lawyer and the president of the Clarke School

for The Deaf, became interested in Bell’s experiments. He and George

Sanders, a prosperous Salem businessman, both sensed Bell might make the

harmonic telegraph work. They also knew Bell the man, since Bell tutored

Hubbard’s daughter and he was helping Sander’s deaf five year old son learn

to speak.

In October, 1874, Green went to Washington D.C. to conduct a patent search.

Finding no invention similar to Bell’s proposed harmonic telegraph, Hubbard

and Sanders began funding Bell. All three later signed a formal agreement

in February, 1875, giving Bell financial backing in return for equal shares

from any patents Bell developed. TThe trio got along but they would have

their problems. Sanders would court bankruptcy by investing over $100,000

before any return came to him. Hubbard, on the other hand, discouraged

Bell’s romance with his daughter until the harmonic telegraph was invented.

Bell, in turn, would risk his funding by working so hard on the telephone

and by getting engaged to Mabel without Hubbard’s permission.

In the spring of 1875, Bell’s experimenting picked up quickly with the help

of a talented young machinist named Thomas A. Watson. Bell feverishly

pursued the harmonic telegraph his backers wanted and the telephone which

was now his real interest. Seeking advice, Bell went to Washington D.C. On

March 1, 1875, Bell met with Joseph Henry, the great scientist and

inventor, then Secretary of the Smithsonian Institution. It was Henry,

remember, who pioneered electromagnetism and helped Morse with the

telegraph. Uninterested in Bell’s telegraph work, Henry did say Bell’s

ideas on transmitting speech electrically represented „the germ of a great

invention.“ He urged Bell to drop all other work and get on with developing

the telephone. Bell said he feared he lacked the necessary electrical

knowledge, to which the old man replied, „Get it!“ [Grosvenor and Wesson]

Bell quit pursuing the harmonic telegraph, at least in spirit, and began

working full time on the telephone.

After llengthy experimenting in the spring of 1875, Bell told Watson „If I

can get a mechanism which will make a current of electricity vary in its

intensity as the air varies in density when a sound is passing through it,

I can telegraph any sound, even the sound of speech.“ [Fagen] He

communicated the same idea in a letter to Hubbard, who remained unimpressed

and urged Bell to work harder on the telegraph. But having at last

articulated the principle of variable resistance, Bell was getting much

closer.

On June 2, 1875, Bell and Watson were testing the harmonic telegraph when

Bell heard a sound come through the receiver. Instead of transmitting a

pulse, which it had refused to do in any case, the telegraph passed on the

sound of Watson plucking a tuned spring, one of many set at different

pitches. How could that be? Their telegraph, like all others, turned

current on and off. But in this instance, a contact screw was set too

tightly, allowing current to run continuously, the essential element needed

to transmit speech. Bell realized what happened and had Watson build a

telephone the next day based on this discovery. The Gallows telephone, so

called for its distinctive frame, substituted a diaphragm for the spring.

Yet it didn’t work. A few odd

sounds were transmitted, yet nothing more. No

speech. Disheartened, tired, and running out of funds, Bell’s experimenting

slowed through the remainder of 1875.

[pic]

During the winter of 1875 and 1876 Bell continued experimenting while

writing a telephone patent application. Although he hadn’t developed a

successful telephone, he felt he could describe how it could be done. With

his ideas and methods protected he could then focus on making it work.

Fortunately for Bell and many others, the Patent Office in 1870 dropped its

requirement that a working model aaccompany a patent application. On

February 14, 1876, Bell’s patent application was filed by his attorney. It

came only hours before Elisha Gray filed his Notice of Invention for a

telephone.

Mystery still surrounds Bell’s application and what happened that day. In

particular, the key point to Bell’s application, the principle of variable

resistance, was scrawled in a margin, almost as an afterthought. Some think

Bell was told of Gray’s Notice then allowed to change his application. That

was never proved, despite some 600 lawsuits that would eventually cchallenge

the patent. Finally, on March 10, 1876, one week after his patent was

allowed, in Boston, Massachusetts, at his lab at 5 Exeter Place, Bell

succeeded in transmitting speech. He was not yet 30. Bell used a liquid

transmitter, something he hadn’t outlined iin his patent or even tried

before, but something that was described in Gray’s Notice.

Bell’s patent, U.S. Number 174,465, has been called the most valuable ever

issued. If you have QuickTime or another way to view .tif files you can

view the document at the United States Patent and Trademark site (external

link). Search for it by the number. Each page of the six page document is

about 230K. And yes, it is very hard to follow. Patents are meant to

protect ideas, not necessarily to explain them . . .

The Watson-built telephone looked odd and acted strangely. Bellowing into

the funnel caused a small disk or diaphragm at the bottom to move. This

disk was, in turn, attached to a wire floating in an acid-filled metal cup.

A wwire attached to the cup in turn led to a distant receiver. As the wire

moved up and down it changed the resistance within the liquid. This now

varying current was then sent to the receiver, causing its membrane to

vibrate and thereby produce sound. This telephone wasn’t quite practical;

it got speech across, but badly. Bell soon improved it by using an

electromagnetic transmitter, a metal diaphragm and a permanent magnet. The

telephone had been invented. Now it was time for it to evolve.

[pic]

How the ffirst telephone worked

Simplified diagram of Bell’s liquid transmitter. The diaphragm vibrated

with sound waves, causing a conducting rod to move up and down in a cup of

acid water. Battery supplied power electrified the cup of acid. As the rod

rose and fell it changed the circuit’s resistance. This caused the line

current to the receiver (not shown) to fluctuate, which in turn caused the

membrane of the receiver to vibrate, producing sound.

This transmitter was quickly dropped in favor of voice powered or induced

models. These transmitted speech on the weak electro-magnetic force that

the transmitter and receiver’s permanent magnets produced.

It was not until 1882, with the introduction of the Blake transmitter, that

Bell telephones once again used line power. The so called local battery

circuit used a battery supplied at the phone to power the line and take

speech to the local switch. Voice powered phones did not go away

completely, as some systems continued to be used for critical applications,

those which may have been threatened by spark. In 1964 NASA used a voice

powered system described as follows:

„A network of 24 channels with a total of more than 450 sound powered

telephones, which derive their power solely from the human voice, provide

the communications between the East Area central blockhouse (left) and tthe

various test stands at NASA’s George C. Marshall Space Flight Center here.

. .“ The complete article is here:

[pic]

IV. The Telephone Evolves

At this point telephone history becomes fragmented and hard to follow. Four

different but related stories begin: (1) the further history of the

telephone instrument and all its parts, (2) the history of the telephone

business, (3) the history of telephone related technology and (4) the

history of the telephone system. Due to limited space I can cover only some

major North American events. Of these, the two most important developments

were the invention of the vacuum tube and the transistor; today’s telephone

system could not have been built without them.

[pic]

Progress came slowly after the original invention. Bell and Watson worked

constantly on improving the telphone’s range. They made their longest call

to date on October 9, 1876. It was a distance of only two miles, but they

were so overjoyed that later that night they celebrated, doing so much

began dancing that their landlady threatened to throw them out. Watson

later recalled „Bell . . . had a habit of celebrating by what he called a

war dance and I had got so exposed at it that I could do it quite as well

as he could.“ [Watson] The rest of 1876, though, wwas difficult for Bell and

his backers.

Bell and Watson improved the telephone and made better models of it, but

these changes weren’t enough to turn the telephone from a curiosity into a

needed appliance. Promoting and developing the telephone proved far harder

than Hubbard, Sanders, or Bell expected. No switchboards existed yet, the

telephones were indeed crude and transmission quality was poor. Many

questioned why anyone needed a telephone. And despite Bell’s patent,

broadly covering the entire subject of transmitting speech electrically,

many companies sprang up to sell telephones and telephone service. In

addition, other people filed applications for telephones and transmitters

after Bell’s patent was issued. Most claimed Bell’s patent couldn’t produce

a working telephone or that they had a prior claim. Litigation loomed.

Fearing financial collapse, Hubbard and Sanders offered in the fall of 1876

to sell their telephone patent rights to Western Union for $100,000.

Western Union refused.

(Special thanks to William Farkas of Ontario, Canada for his remarks and

corrections)

In 1876 Ericsson begins.

[pic]

In1878, the Butterstamp telephone came into use. This telephone combined

the receiver and transmitter into one handheld unit. You talked into one

end, turned the instrument round and listened to the other end. People got

confused with this clumsy arrangement, consequently, a telephone with a

second transmitter and receiver unit was developed in the

same year. You

could use either one to talk or listen and you didn’t have to turn them

around. This wall set used a crank to signal the operator.

[pic]

The Butterstamp telephone.

On August 1, 1878 Thomas Watson filed for a ringer patent. Similar to

Henry’s classroom doorbell, a hammer operated by an electromagnet struck

two bells. Turning a crank on the calling telephone spun a magneto,

producing an alternating or ringing current. Previously, people used a

crude thumper to signal the called party, hoping someone would bbe around to

hear it. The ringer was an immediate success. Bell himself became more

optimistic about the telephone’s future, prophetically writing in 1878 „I

believe that in the future, wires will unite the head offices of the

Telephone Company in different cities, and that a man in one part of the

country may communicate by word of mouth with another in a distant place.“

Subscribers, meanwhile, grew steadily but slowly. Sanders had invested

$110,000 by early 1878 without any return. He located a group of New

Englanders wwilling to invest but unwilling to do business outside their

area. Needing the funding, the Bell Telephone Company reorganized in June,

1878, forming a new Bell Telephone Company as well as the New England

Telephone Company, a forerunner of the strong regional Bell ccompanies to

come. 10,755 Bell phones were now in service. Reorganizing passed control

to an executive committee, ending Hubbard’s stewardship but not his overall

vision. For Hubbard’s last act was to hire a far seeing general manager

named Theodore Vail. But the corporate shuffle wasn’t over yet. In early

1879 the company reorganized once again, under pressure from patent suits

and competition from other companies selling phones with Edison’s superior

transmitter. Capitalization was $850,000. William H. Forbes was elected to

head the board of directors. He soon restructured it to embrace all Bell

interests into a single company, the National Bell Company, incorporated on

March 13, 1879. Growth was steady enough, however, that in late 1879 the

first telephone numbers were used.

On November 10, 1879 Bell won its patent infringement suit aagainst Western

Union in the United States Supreme Court. In the resulting settlement,

Western Union gave up its telephone patents and the 56,000 phones it

managed, in return for 20% of Bell rentals for the 17 year life of Bell’s

patents. It also retained its telegraph business as before. This decision

so enlarged National Bell that a new entity with a new name, American Bell

Company, was created on February 20, 1880, capitalized with over seven

million dollars. Bell now managed 133,000 telephones. As Chief Operating

Officer, Theodore VVail began creating the Bell System, composed of regional

companies offering local service, a long distance company providing toll

service, and a manufacturing arm providing equipment. For the manufacturer

he turned to a previous company rival. In 1880 Vail started buying Western

Electric stock and took controlling interest on November, 1881. The

takeover was consummated on February 26, 1882, with Western Electric giving

up its remaining patent rights as well as agreeing to produce products

exclusively for American Bell. It was not until 1885 that Vail would form

his long distance telephone company. It was called AT&T.

[pic]

On July 19, 1881 Bell was granted a patent for the metallic circuit, the

concept of two wires connecting each telephone. Until that time a single

iron wire connected telephone subscribers, just like a telegraph circuit. A

conversation works over one wire since grounding each end provides a

complete path for an electrical circuit. But houses, factories and the

telegraph system were all grounding their electrical circuits using the

same earth the telephone company employed. A huge amount of static and

noise was consequently introduced by using a grounded circuit. A metallic

circuit, on the other hand, used two wires to complete the electrical

circuit, avoiding the ground altogether and thus providing a better

sounding call.

Depending on local conditions and economies, some iindependent telephone

companies did not introduce two wire for decades after. Consider this

example from the Magazine Telephone Company of central Arkansas: „After the

end of WW II, the R.E.A. System was introduced to the area. This

electrification project induced noise into the one wire magneto system that

was currently in use by the Telephone Company. Henry [Stone] converted the

magneto system to a new system called common battery. Instead of just one

wire, common battery required two metallic wires for each circuit.“

For a short but well detailed history of an independent telco, visit the

Magazine Telephone Company:

On February 28, 1885 AT&T was born. Capitalized on only $100,000, American

Telephone and Telegraph provided long distance service for American Bell.

Only local telephone companies operating under Bell granted licenses could

connect to AT&T’s long distance network. Vail thought this would continue

the Bell System’s virtual monopoly after its key patents expired in the

1890s. He reasoned the independents could not compete since they would be

isolated and without long distance lines. With licensed companies providing

local service, Western Electric manufacturing equipment and AT&T providing

long distance, Vail’s structuring of the Bell System was now complete.

In 1964 the Bell System put its star crossed videotelephone into limited

commercial service between New York, Washington and Chicago. Despite

decades of dreaming, development aand desire by Bell scientists, technicians

and marketing wonks, the videotelephone never found a market. [pic]

GTE was then a poorly managed conglomerate of 23 regional phone companies

and a maker of, among other things, televisions and light bulbs. They had

their successes and failures. One notable achievement is below.

„Introducing a crimestopper so advanced Dick Tracy doesn’t have it yet.“

[pic]

In1971 General Telephone and Electronics (GTE Sylvania) introduced a data

system called Digicom. It let dispatchers identifying patrol car locations

on a screen, and allowed officers to run license plate checks. When a

patrolman touched a spot on the digicom screen it lit up the same spot on

the dispatcher’s map. Produced by their Sociosystems Products Organization,

I do not know how many units were actually installed by GTE, but it

certainly foreshadowed later developments. Today many police departments

use cellular digital packet data (CDPD) to run plates and communicate in

text with their dispatchers. CDPD runs on existing cellular networks, with

data rates no more that 9.6 or 19.2 Kbs, adequate for most purposes but

slow when you consider that in the year 2000, 29 years after this system

was introduced, we are still laboring with creeping data rates. Click on

the image above or here to get the full picture and story. (It’s a huge

graphic

file so be careful: 364K)

1968. Even the astute Japanese fell victim to developing picturephones as

this unflattering photograph shows, this model was probably developed by

Nippon Telephone and Telegraph

In 1982 the Bell System had grown to an unbelievable 155 billion dollars in

assets (256 billion in today’s dollars), with over one million employees.

By comparison, Microsoft in 1998 had assets of around 10 billion dollars.

On August 24, 1982, after seven years of wrangling, the Bell System was

split apart, succumbing to government pressure from without aand a carefully

thought up plan from within. Essentially, the Bell System divested itself.

Kaunas Technology University

Darbą atliko:Rima Jakučionytė,

Nerijus Kalinka

Tikrino:dėstytoja V.Šeštokova