Morse Code, Telegraph, Binary System, Bit, Byte, Bitstream, Dialup Modems, Broadband, Cable Modem and Coaxial Cable

Posted by PITHOCRATES - August 8th, 2012

Technology 101

One of the First Improvements in Communication Speed was Morse Code sent on a Telegraph

The Battle of New Orleans (1815) was a great American victory over the British.  General Andrew Jackson with a force of about 4,000 repulsed a British force of some 11,000.  It was a huge American win.  The biggest in the war.  And a humiliating British defeat.  Now here’s an interesting side note about that battle.  The war was already over.  We had already signed a peace treaty with the British.  And were already repairing that special relationship between the United States and Britain.  So why was there even a Battle of New Orleans?  Because there was no Internet, television, radio or telegraph back then.  There was only ink and paper.  And foot, horse and boat.  Making communications slow.  Very, very slow.

The American Civil War, like the Crimean War, was a war where the technology was ahead of the tactics.  Four years of fighting with modern weapons using Napoleon tactics killed over half a million Americans by 1865.  After General Grant flushed General Lee from the Petersburg defenses he chased him as Lee fled west.  With General Sheridan’s cavalry in hot pursuit.  Cutting in front of Lee’s army to bring on the Battle of Sayler’s Creek.  Where the Confederates suffered a crippling defeat.  General Sheridan telegraphed General Grant, “If the thing is pressed, I think that Lee will surrender.”  President Lincoln was monitoring the military wires in Washington.  When he read Sheridan’s message he quickly sent a wire to General Grant.  “Let the thing be pressed.”  Grant pressed the thing.  And Lee surrendered at Appomattox Courthouse.

In 50 years time communications went from taking weeks.  To taking as little as minutes. The benefit of faster communications?  At the Battle of New Orleans approximately 2,792 people were killed, wounded or went missing.  In a battle fought after the war was over.  Only word hadn’t gotten to them yet.  So fast communications are a good thing.  And can prevent bad things from happening.  And one of the first improvements in communication speed was Morse code sent on a telegraph.  A wire between two places.  With a key switch and an electromechanical device at each end.  When an operator tapped the switch closed an electrical current went down the wire to the electromechanical device at the other end of the wire, inducing a current in it that opened and closed a device that replicated the keying at the other end.  Thus they could send a series of ‘dots and dashes’ through this wire.  The operator encoded the message at one end by assigning a series of dots and/or dashes for each letter.  The operator at the other end then decoded these dots and dashes back into the original message.

Getting Outside Information into your Computer was a little like Getting Information over a Telegraph

Morse code is a binary system.  Just like the ‘bits’ in a computer system.  Where each bit was one of two voltage levels.  Represented by 1s and 0s.  Eight bits make a byte.  Like the telegraph operator a man-machine interface encodes information into a series of bits.  The computer bus, registers and microprocessor ‘grab’ bytes of this bitstream at a time.  And then processes these bits in parallel blocks of bytes.  Unlike the telegraph where the encoded message went serially down the wire.  The telegraph greatly increased the speed of communications.  But a telegraph operator could only encode and send one letter of a word at a time.  So he couldn’t send many letters (or pulses) per second.  Just a few.  But when you encode this information into 8-bit chunks you can greatly increase the speed data moves inside a computer.  As computer speeds grew so did their bus size.  From 8 bit to 16 bit (2 bytes).  From 16 bit to 32 bit (4 bytes).  From 32 bit to 64 bit (8 bytes).  As a computer processed more bytes of data at a time in parallel computers could increase the speed it completed tasks.

Of course, people who were most interested in faster computers were gamers.  Who played games with a lot of video and sound information encoded in them.  The faster the computer could process this information the better the graphics and sound were.  Today computers are pretty darn fast.  They can run some of the most demanding programs from 3-D gaming to computer-aided design (CAD).  But then a new technology came out that made people interested by what was happening outside of their computer.  And how fast their computer was didn’t matter as much anymore.  Because getting that outside information into your computer was a little like getting information over a telegraph.  It came in serially.  Over a wire.  Through a modem that attached a computer to the Internet.  And the World Wide Web.  Where there was a whole lot of interesting stuff.  But to see it and hear it you had to get it inside your computer first.  And the weak link in all your web surfing was the speed of your modem.

A modem is modulator-demodulator.  Hence modem.  And it worked similar to the telegraph.  There was a wire between two locations.  Typically a telephone line.  At each end of this wire was a modem.  The wire terminated into each modem.  Each modem was connected to a computer.  One computer would feed a bitstream to its modem.  The modem would encode the 1s and 0s in that bitstream.  And modulate it onto a carrier frequency.  The modem would output this onto the telephone line.  Where it traveled to the other modem.  The other modem then demodulated the carrier frequency.  Decoded the 1s and 0s and recreated the bitstream.  And fed it into the other computer.  Where the computer grabbed bytes of the bitstream and processed it.

The Coaxial Cable of Broadband could Carry a wider Range of Frequencies than the Twisted Pairs of Telephone Wire

The speed at which all of this happened depended on your modem.  Specifically your modem.  The other modem you connected to was typically on a web server and was of the highest speed.  And on all of the time.  Unlike the early dialup modems we used in the Nineties when we first started surfing the web.  Back then surfing could be expensive as you often paid for that time as if you were on the telephone.  This was the other weak link in surfing.  Trying to make that telephone line as short as possible.  Because that was what you paid for.  The use of the telephone line.  Once you got onto the Internet you could travel anywhere at no additional cost.  So you dialed in to an available local number.  Which sometimes could take awhile.  And when you finally did dial-up on a local line but went inactive for a period of time it disconnected you.  Because others were looking for an available local phone line, too.

The first modem speeds many of us used at the beginning were 2400 bits per second (bps).  Which was a lot faster than the few bits per second of a telegraph operator.  And okay for sending email.  But it was painfully slow for graphics and sound.  And then the improvements in speed came.  And they came quickly.  4800 bps.  9600 bps.  14400 (14.4k) bps.  28800 (28.8k) bps.  33600 (33.6k) bps.  And then the last of the dialup modems.  56000 (56k) bps.  Which meant you could download up to 56,000 bits per second of 1s and 0s.  That’s 56,000 pieces of information coming out of that modem each second.  Now that was fast.  Still slower than what happened inside the computer with those wide parallel buses.  That chomped off huge bytes of data.  And processed them at rates in excess of a billion times a second.  But it was still the fastest thing on the block.  Until broadband arrived.

Today you can buy a broadband cable modem for less than $100 that can download at speeds in excess of 100,000,000 bits per second.  That’s over 100 million pieces of information each second.  It is only data rates like this that let you live stream a movie off the Internet.  Something that the 56k modem just wouldn’t do for you.  And it’s always on.  Costing you a flat fee no matter how long you spend surfing the web.  You turned on your computer and you were connected to the Internet.  What allowed those greater speeds?  The wire.  The coaxial cable of broadband could carry a wider range of frequencies than the twisted pairs of the telephone wire.  Providing a greater bandwidth.  Which could carry more encoded information between modems.  Allowing you to download music and videos quicker than it took a telegraph operator to send a message.

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