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[Footsteps]

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[Jazzy music: 'The Russians Are Coming' - Val Bennett]

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[ring ring]
[ring ring]

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Tim: Hello?

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It's a miracle of the age being able to pick up the phone and talk to somebody on the other side of the world.

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But although this needs some very sophisticated electronics connecting the phone together

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the telephone itself has remained quite a simple gadget.

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It's really just a set of push buttons,

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a couple of switches,

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a bit of electronics inside,

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a bell or a buzzer of some sort,

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and of course the handset.

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Well, err, take the microphone out and give it to Rex.

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The microphone and the earpiece are remarkably similar

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to those on the very first telephone invented over 100 years ago.

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If I connect up the earpiece at this end...

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and, er,  Rex connects up the microphone at the other end...

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I should be able to hear him.

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Rex: Hallo, can you hear me Tim?

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Rex: (faintly through speaker) Can you hear me?

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Tim: Yes I can, it works very well.

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This is too faint to work over long distances

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but the remarkable thing is that there's no battery in this circuit,

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it's just the microphone at one end, and the earpiece at the other.

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In this programme I am going to look at how the telephone evolved from

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simple devices like this, to become the elaborate international system that it is today.

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Rex (into microphone) Hallo Tim. Can you hear me?

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It had been discovered in 1820 that any wire carrying electricity becomes slightly magnetic.

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The effect was called electromagnetism.

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Wrapping round, the wire round in a coil, greatly increases the effect.

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[Clank]

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The extraordinary thing is that until 25 years ago

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most of the telephone system was worked by devices based on this simple effect.

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The first use of the electromagnet though was for the teleGRAPH

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which in many ways was the forerunner of the telePHONE.

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In its simplist form, you simply had a switch at one end...

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Tim: Rex?

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[Quiet clicking noise]

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Tim: And a needle at the other.

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This was made in lots of different varieties

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This is a, one for sending private messages.

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This is a twin-needle one, and you could send

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all the different letters of the alphabet by a sort of

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code of different sequences of needle movements.

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This is a replica of Samuel Morse's original apparatus

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it was quite elaborate at first.

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You had to turn this handle to send the messages

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[squeaking] [cogs grinding and clanking]

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And the receiver printed the messages out on a strip of paper.

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But the operators soon realised they could simply tap the message out

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and decipher the signal by simply listening to it.

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and this was the origin of Morse code.

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This was a system for unskilled operators

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you had one switch for each letter of the alphabet

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and if I press the 'R' and turn the handle

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The receiving station would have an identical instrument

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and the needle in the middle would go round to the same letter.

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This is a more primitive version of the same thing.

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Well, by 1860 the telegraph system had become big business

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all the major towns in Europe and America had a telegraph station.

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the lines became so busy that, er, they had to develop a way of sending the messages at high speed.

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So you had somebody printing the messages out on paper tape,

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and putting them into one of these machines that was a high speed sender

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[gearbox whine and rapid clicking noise]

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And at the other end, you had one of these machines which is an inking machine.

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[clanking in recognisable morse code pattern]

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Not working at very high speed at the moment.

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[clattering in morse]

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Okay, that's enough of that!

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Well this required a whole army of clerks which had to punch the messages out

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and then decipher them at the other end.

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It was while trying to invent an improved version of this,

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that Alexander Graham Bell realised that it might be possible

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to send speech down the wires instead of simple pulses.

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Bell's father was an ebullient teacher of elocution and speech therapy in Edinburgh.

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Bell Snr: Graham, now listen to this poor woman.

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Bell Snr: She has the most terrible problems with those labials.
Woman: Around the ragged... Around the ragged...  Aaah!

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Bell Snr: Och and she's got a frightful lisp too.

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Tim: However, Graham's two brothers then died of tuberculosis

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and his father then decided to emigrate to a healthier climate.

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[bagpipes playing mournful tune]
Mrs Bell: [sobbing]

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Bell Snr: And they had such lovely voices too.

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Bell Snr: We'll do fine in America.

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Woman: (Boston accent) Around the ragged rack...

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Tim: Aged 25, Bell started teaching speech therapy himself in Boston.
[Woman drawls in background]

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At the same time he came up with his idea of a harmonic telegraph.

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Recruiting a man from the local ironmonger's shop called Watson,

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He experimented sending several messages simultaneously at different tones,

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but nothing would make it work.

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Bell: Och, it doesnae werk!

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On June 2nd 1875 though,

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he suddenly realised it could be modified to transmit speech.

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[cymbal clash]

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Tim: Bell described what he'd done as transmitting voice-shaped currents.

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Instead of the electromagnet just being on or off...

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[clink] [clang]

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...he was using it to vibrate a diaphragm and produce sounds.

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Well if Rex now connects the electromagnet to my record player...

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...and we use the bass drum skin as the diaphragm...

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erm you should be able to hear something.

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[Bassey, indistinct 'The Russians Are Coming']

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Tim: The magnet's vibrating the skin and this is moving the air

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reproducing the original sound.

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This is one of Bell's original telephones. You can see exactly the same arrangement

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with a diaphragm here, and electromagnet.

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You listen in through the bottom here.

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This is a modern telephone earpiece

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and you can see this has a metal diaphragm

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and the electromagnet is embedded in plastic down the bottom.

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The principle is exactly the same

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Bell's patents made him a very rich man

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and he built an enormous mansion in Nova Scotia.

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He grew rather portly and started experimenting with

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kites, twin-bearing sheep, iron lungs, hydrofoils, and all things.

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He became completely fed up with the telephone, and wrote:

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"I have become so detached from it, I often wonder

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if I really did invent it, or was it just someone else I'd read about."

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Bell used a second receiver as his microphone.

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It works exactly in reverse:

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When you speak near it, the diaphragm vibrates

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and creates a tiny electric current in the electromagnet.

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I  can show you this with a loudspeaker

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A loudspeaker is just a larger version of the same thing, really,

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with a paper cone as a diaphragm and an electromagnet underneath.

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I connected it to a meter here and when

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I move the diaphragm
[thudding on speaker cone]

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the meter measures the current.

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Well now, if I connect it to a second speaker...

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When I vibrate one speaker...
[thud thud thud]

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[rattle rattle rattle]

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...the other one vibrates too.

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This is how Rex was managing to talk to me at the beginning of the programme.

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but it's not a very efficient process this, which is why Rex's voice was so faint.

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and without any electronics, Bell's idea was much too faint to be of any practical use at all.

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Rex: The first practical telephone used a completely different type of microphone.

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This was patented by Thomas Edison, some two years after Bell.

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Edison realised that if you apply a small amount of pressure

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to a lump of carbon, its resistance changed.

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So he fitted a diaphragm to a piece of carbon.

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This basic idea was greatly improved by a Rev. Hunnings:

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he used a whole pile of carbon granules.

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And we can reproduce this, quite easily, using a coffee jar top.

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I've put a couple of bits of silver paper in here to form a contact

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and connecting up to a loudspeaker and a battery...

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If I fill this with the granules, you'll hear it begin to crackle...

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[loud amplified crackling noise]

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then fit a diaphragm, which is just a piece of plastic...

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[more amplified crackling when Rex taps]

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If I cup my hands round it, and speak quite loudly, you should be able to hear

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(amplified through speaker) Bell's voice shaped currents coming out of the speaker.

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And this type of microphone, in a refined version,

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was used in telephones right up until the late '70s.

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[Doomful piano music]

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Tim: With Bell's receiver and Edison's microphone

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the telephone became a practical propoition.

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[doomful music continues]

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At first the telephone companies had to stress its usefulness in emergencies

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because so few people had phones, they weren't much use for anything else.

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This is part of a film made for a New York phone company in 1910.

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[piano music continues]

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The company's efforts were obviously successful.

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This is a pile of New York telephone directories a few years later.

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This is one of Edison's first telephones

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you have to turn the handle all the time to hear anything through it.

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It's called a chalk receiver.

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This one's called the marriage,

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it's one of the (first) phones to combine Bell's receiver and Edison's microphone.

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A lot of the early phones didn't have microphones as such,

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but they just had these wooden sounding boards which acted as the diaphragm

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you just had to speak somewhere near them.

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This is the bell that called the attention of the operator.

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This one's the horse collar phone

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that you put your head right in it...

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[Tim mumbles into telephone]

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...for private conversations.

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One thing that most of these early phones had in common,

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was that the microphone was firmly fixed to the wall or a base.

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And this stopped the carbon granules moving around and crackling too much.

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The candlestick phone which came into fashion in the '20s, was a sort of compromise,

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although you could move the microphone around,

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it tended to keep the carbon granules at the same angle as you lifted it up.

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Carbon microphones were gradually improved until they could be fitted into handsets.

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And in fact many are still in use, crackling away.

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[clunk]

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None of the early phones had dials,

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you simply asked the operator at the exchange to

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connect you to the number you wanted.

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Early attempts at using male operators are said

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to have been unacceptable because they were too rude.

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As the telephone system expanded more and more telephone operators were needed.

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Operators: # With trunks and toll and telegrams, and all exchanges too.

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# Just telephone and we will put you through!

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# Ring Arbour Corner Archway.  Ring Mayfair, Hop or Sloane.

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# Ring anywhere, we're waiting on your phone.

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# Do you want a little warning to make you get up in the morning?

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# Is your house on fire?

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# Do you want to send a wire?

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# Just lift up the receiver,

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# that's all you've got to do,

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# to telephone, and we will put you through! #

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The rapidly growing number of telephone operators

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increased the incentive for some sort of automatic switching system.

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The answer was provided by the versatile electromagnet.

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I still use electromagnetic switches called relays in a lot of the machines I make.

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This is a nutcracker I made for an exhibition

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[whirring]

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[whirring and squeaking]

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The relays control the motor,

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it's actually quite useful to be able to see what's going on

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and they're actually quite reliable.

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You can see one of their disadvantages though
[Click whirrr]

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the sparks gradually erode the contacts away.
[buzzz click whirr]

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[whirrr] [thunk]

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The first automatic exchange was designed in desperation by

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an undertaker from Kansas city called Almon B Strowger in 1889

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Strowger: Hmm, not enough people dying hereabouts.

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Unless there's sommat funny going on...

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Lets see, there's my arch-rival Mc Greedly.

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Hmmm. He seems mighty busy all of a sudden.

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[horse cart rattles]

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There's Mrs McGreedly going to work at the telephone exchange.

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Heeyyy!  Telephone!

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McGreedly: So sorry to hear about your recent bereavement,

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but we do have a special offer this week.

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six coffins for the three ... interior...
Strowger: That's It! She tells em who's dyin'!

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[scrabbling noise]

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So I make my own telephone exchange and cut out the third party.

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This is a strowger selector made in the 1960s

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and it's still surprisingly similar.

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There are two electromagnets, one makes this arm climb up

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[kerklunk kerklunk kerclunk]

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And the other ones makes it hunt across...

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[kerklunk kerklunk kerklunk]

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And finally resets it...

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Behind there's a large bank of contacts

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the arm sits in front.

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This connects to the dial.

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[clickclickclickclick]
[whirrrrr]

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These are the clicks that you hear, when, err, whenever you dial a number.

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[clickclickclickclick]
[whirrrrr]

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00:15:47,276 --> 00:15:48,987
[loud noisy environment]

242
00:15:48,988 --> 00:15:53,102
Many Strowger exchanges are still in use, this one's in Norwich.

243
00:15:53,103 --> 00:15:56,923
although Strowger only imagined tiny exchanges with one contact

244
00:15:56,924 --> 00:16:00,848
for each subscriber his selectors were soon being connected together

245
00:16:00,849 --> 00:16:03,510
to make larger exchanges like this.

246
00:16:05,661 --> 00:16:09,370
The engineers call the system affectionately, 'Click and Bang'.

247
00:16:09,371 --> 00:16:12,468
Keeping it all working is quite an undertaking -

248
00:16:12,869 --> 00:16:16,516
the contacts tend to get dirty and make the lines noisy.

249
00:16:16,517 --> 00:16:19,624
And the selectors need precise adjustment to work properly.

250
00:16:20,025 --> 00:16:25,346
Also the mechanism gradually sheds tiny metal filings literally wearing itself out.

251
00:16:25,547 --> 00:16:28,008
It's quite surprising it works at all.

252
00:16:28,009 --> 00:16:30,873
[clicketyclicketyclickety]

253
00:16:36,780 --> 00:16:41,262
There quickly reaches a level where electromechanical devices become a bit absurd.

254
00:16:41,263 --> 00:16:42,285
[clank thunk]

255
00:16:42,286 --> 00:16:45,292
This is a burglar enunciator built in the 1930s...

256
00:16:45,876 --> 00:16:49,676
[crackle]
Male voice on recording: These premises are being broken into,

257
00:16:50,077 --> 00:16:57,571
Po-lice, Scotland Yard.  Po-lice, Scotland Yard.  Po-lice, Scotland Yard.

258
00:16:57,572 --> 00:17:05,950
This is a Burgot automatic burglar alarm. Operating at: 'Jay' 'Eee' 'Ell'...

259
00:17:05,951 --> 00:17:08,346
Tim: The solution was a whole new technology with no moving parts.

260
00:17:09,347 --> 00:17:15,921
Which was based on a device invented for telephone exchange switching in 1947, the transistor.

261
00:17:16,122 --> 00:17:21,256
It was credited to John Bardeen, Walter Brattain and William Shockley

262
00:17:21,257 --> 00:17:25,101
Bardeen was the mathematician who developed the theory.

263
00:17:27,194 --> 00:17:30,974
Brattain was the practial experimentor who actually tried things out.

264
00:17:32,392 --> 00:17:37,179
Shockley was the leader of the team, a visionary aloof from the day-to-day experiments.

265
00:17:37,799 --> 00:17:41,218
He foresaw more advanced transistors developed years later,

266
00:17:41,219 --> 00:17:46,370
and finally disgraced himself with his campaign for bribing people with low IQs to be sterilised.

267
00:17:46,371 --> 00:17:51,027
Shockley: Okay fella, you take the money and it won't hurt too much, okay?
Fella: Ooooh!

268
00:17:51,028 --> 00:17:53,414
Tim: This is a modern transistor,

269
00:17:53,415 --> 00:17:58,262
a small amount of current in one side switches a much larger amount on the other side.

270
00:17:59,495 --> 00:18:04,660
Here I've hooked up the high power side of a transistor to a car battery and a headlight.

271
00:18:04,661 --> 00:18:08,172
And er, if I moisten my fingers...

272
00:18:08,173 --> 00:18:13,947
I can now switch the transistor with the tiny amount of current passing through my body.

273
00:18:13,948 --> 00:18:16,795
Just touching the low power side of the transistor

274
00:18:16,796 --> 00:18:19,254
is enough to switch the light on and off.

275
00:18:23,034 --> 00:18:26,506
Solid state switching like this has enormous advantages

276
00:18:26,507 --> 00:18:31,266
there are no mechanical parts to wear out, and of course they're no contacts to spark across.

277
00:18:36,430 --> 00:18:38,565
[click] [click]

278
00:18:38,566 --> 00:18:42,643
This dummy I made for a shopping centre had to work 12 hours a day.

279
00:18:43,040 --> 00:18:45,579
And I worked out the "Spend, Spend, Spend" lights

280
00:18:45,580 --> 00:18:48,092
would be switching over 6 million times a year. 

281
00:18:48,093 --> 00:18:49,649
[pneumatic whooshing noise]

282
00:18:49,650 --> 00:18:51,888
Electromagnetic relays wouldn't have lasted long,

283
00:18:51,889 --> 00:18:54,438
but with transistors it should last for ages. 

284
00:18:55,010 --> 00:18:58,219
Transistors can actually switch millions of times a second,

285
00:18:58,220 --> 00:19:01,686
so fast that speech can be converted to a sort of code

286
00:19:01,687 --> 00:19:05,103
consisting of a very rapid string of on and off pulses. 

287
00:19:05,104 --> 00:19:10,618
this digital code has a better quality, just like the digital sound of compact discs. 

288
00:19:10,619 --> 00:19:14,822
And it also enables the sound to be processed by digital computers.

289
00:19:14,823 --> 00:19:19,629
[callcentre noise] ..5698, 135, thank you, what's your number please? 

290
00:19:19,706 --> 00:19:20,705
[clunk]

291
00:19:20,906 --> 00:19:24,026
[fileofax rattles] [clunk of removed plug]

292
00:19:24,027 --> 00:19:28,194
Today, computers are transforming telephone exchanges dramatically.

293
00:19:28,195 --> 00:19:35,136
The operator switchboard, little changed from 1900, is being replaced by these computer keyboards. 

294
00:19:40,552 --> 00:19:44,479
The new digital exchange controll room looks just like an ordinary office. 

295
00:19:45,611 --> 00:19:47,597
The system's increadibly reliable 

296
00:19:47,598 --> 00:19:51,683
failed connections have been reduced from 5% to 0.01%.

297
00:19:51,684 --> 00:19:54,190
So there's much less for the engineers to do. 

298
00:19:55,187 --> 00:19:59,504
Occasionally the computer does find a fault and tells them to change a panel. 

299
00:20:00,948 --> 00:20:02,912
[noise of lots of computers and associated aircon]

300
00:20:07,580 --> 00:20:13,811
The engineer first has to earth himself, to prevent any static electricity from damaging the chips.

301
00:20:16,639 --> 00:20:20,388
The panel simply gets posted away to be repaired,

302
00:20:20,389 --> 00:20:25,199
the engineers say there is much less job satisfaction than with the old 'Click and Bang' system. 

303
00:20:25,200 --> 00:20:31,762
They all go home at 4:30pm and the exchange is then completely controlled from Cambridge until the next morning. 

304
00:20:36,262 --> 00:20:40,885
Like the digital exchange, modern telephones now use electronics. 

305
00:20:40,886 --> 00:20:44,821
This has enabled them to go back to Bell's elegant original idea 

306
00:20:44,822 --> 00:20:48,532
of having an identical earpiece and microphone. 

307
00:20:50,253 --> 00:20:53,856
Rex (from speaker): Hallo! Can you hear me better now that it's amplified?

308
00:20:53,857 --> 00:20:57,574
Tim: It's now so loud that I hardly have to hold it to my ear at all

309
00:20:57,575 --> 00:21:01,715
and the sound quality's much better than Edison's crackly carbon microphone. 

310
00:21:01,716 --> 00:21:06,330
All thanks to this tiny transistor amplifier. 

311
00:21:06,680 --> 00:21:11,809
[Clunk] (tinny voice) It's surprising what you can do with transistor amplifiers 

312
00:21:11,810 --> 00:21:15,950
you're listening to me now through a device that Rex gave me for Xmas last year 

313
00:21:15,951 --> 00:21:17,849
When he takes it away from the glass...

314
00:21:17,850 --> 00:21:22,157
[silence] 

315
00:21:22,158 --> 00:21:26,100
[Clunk] Now he's put it back again, you can hear me quite clearly again. 

316
00:21:29,544 --> 00:21:33,428
Rex: This little acoustic probe can only pick up minute vibrations,

317
00:21:34,129 --> 00:21:37,645
and the window is acting as a diaphragm, exactly as a microphone. 

318
00:21:37,646 --> 00:21:43,752
It's got several serious uses, we can use to detect, er, a noise on a car engine 

319
00:21:43,753 --> 00:21:47,934
so you can actually tell which tappet is making a noise, or which bearing has failed. 

320
00:21:47,935 --> 00:21:52,728
It's got lighthearted uses as well, erm, you can actually hear through a 9" wall 

321
00:21:52,729 --> 00:21:57,177
far better than an upturned wine glass like grandmother used to use. 

322
00:21:57,178 --> 00:22:02,410
Erm, you can also as you see, listen through glass as if it wasn't there. 

323
00:22:02,411 --> 00:22:05,882
The other advantage of electronics is that it's also compact. 

324
00:22:05,883 --> 00:22:09,417
the latest chips and circuits are so small that there's room

325
00:22:09,418 --> 00:22:14,473
 for a radio transmitter and receiver as well - the cordless phone.

326
00:22:14,474 --> 00:22:20,514
There's even room for the very sophisticated electronics in a cellphone 

327
00:22:20,515 --> 00:22:22,942
which automatically changes the frequency of its radio 

328
00:22:22,943 --> 00:22:26,463
as it passes from one transmitter cell to the next. 

329
00:22:29,397 --> 00:22:34,230
Without the large bell and dial mechanism that used to fill the traditional designs,

330
00:22:34,231 --> 00:22:37,544
telephones have lost their distinctive, robust appearance.

331
00:22:38,555 --> 00:22:42,040
The electronics will fit in almost any size or shape. 

332
00:22:42,816 --> 00:22:47,672
Perhaps the most striking thing about modern phones is their sheer quantity. 

333
00:22:47,673 --> 00:22:51,527
It wasn't long ago that it was extraordinary to have more than one phone in the house. 

334
00:22:51,528 --> 00:22:56,221
[50s music]

335
00:22:56,222 --> 00:22:57,389
Woman: Further more...

336
00:22:57,390 --> 00:22:59,999
# A kitchen phone at hand when friends call up to chat a bit...

337
00:23:00,000 --> 00:23:05,747
[music] [phone rings] 

338
00:23:05,748 --> 00:23:08,707
# Hello, yes it is Mary. How are you? Bye.

339
00:23:08,708 --> 00:23:11,621
Caller: # They say your kitchen dazzles every eye! 

340
00:23:11,622 --> 00:23:14,830
Woman: # A brand new sink, a built in ov-en...

341
00:23:14,831 --> 00:23:17,490
# a new refrigerator, and a phone,

342
00:23:17,491 --> 00:23:18,907
# A kitchen phone!

343
00:23:18,908 --> 00:23:20,378
# A bright red phone!

344
00:23:20,379 --> 00:23:24,219
# I gotta go. Goodbye goodbye goodbye!

345
00:23:24,220 --> 00:23:26,202
# I'll call you later! #

346
00:23:26,203 --> 00:23:31,233
[perky music] 

347
00:23:31,234 --> 00:23:36,604
[music becomes slower, more romantic and calm]

348
00:23:37,205 --> 00:23:42,121
Tim: Today most homes have at least two phones, and often a cordless one as well. 

349
00:23:42,122 --> 00:23:45,896
And with a cellphone you can be in touch almost all the time, wherever you are. 

350
00:23:45,897 --> 00:23:50,661
The number of phonelines in Britain alone is growing by about a million a year. [ring ring]

351
00:23:50,662 --> 00:23:55,023
It's all very convenient but the telephone does now seem to rule our lives. 
[ring ring]

352
00:23:55,024 --> 00:23:59,460
it's almost impossible not to answer it when it rings. 
[ring ring] [ring ring]

353
00:23:59,961 --> 00:24:02,159
[clank] Man: Oh! What! 

354
00:24:02,160 --> 00:24:05,637
[water sloshing]
Woman: Oh Help!

355
00:24:05,638 --> 00:24:07,662
Man: (wearily) Oh Dear!
[ring]

356
00:24:07,663 --> 00:24:09,755
[ring]
Woman: Hello?

357
00:24:09,956 --> 00:24:14,671
Woman: Wrong number!
All: Oh! No! 

358
00:24:14,672 --> 00:24:20,835
Tim: People talk about going away on holiday today to get away from the phone...
[Ring] Man: Hello Lofty...

359
00:24:20,836 --> 00:24:22,136
All: "Oh No!" "Really!"

360
00:24:22,137 --> 00:24:29,217
Tim: I doubt whether Bell would have foreseen how dependent the world would become on his ingenious invention. 

361
00:24:29,218 --> 00:24:31,553
But I'm quite certain that he would never have guessed

362
00:24:31,554 --> 00:24:35,895
the elaborate lengths that some people would go to disguise the things. 

363
00:24:36,196 --> 00:25:43,477
[Jazzy music: 'Take 5' - Dave Brubeck]