If you're old enough to remember this noise--
[DIAL-UP MODEM SOUNDS]
--then you're probably feeling that nostalgia right now,
right?
You probably, though, had no idea what
was actually happening here.
I mean, all I cared about was the sound that came after--
You've got mail.
--or maybe this one.
[COMPUTER CHIMING]
I'm getting tingles just listening to the sound
again and again.
But I have questions.
[THEME MUSIC PLAYING]
Welcome to Uno Dos of Trace.
This week, modem sounds.
These sounds actually do have meaning.
I'm sure you knew that.
It's computer speak, or modem speak really.
Modem is actually a compound word for modulator/demodulator,
modem.
The idea is it uses wires to send signals between two
computers, be that a government computer to another government
computer, a researcher to a central computer
or a supercomputer, or your little PC in your house to AOL,
a BBS, a usenet, or Facebook, or wherever.
Even the mighty cell phone, the pinnacle
of modern computing in your pocket, has a modem in it.
For governments and research institutions,
the original lead hackers, the set line
was dedicated completely to the modem,
sort of like a telegraph line.
It connected the two things together, and that was it.
That was in the early 20th century.
Modems are way older than you think.
But then during World War II, the Air Force
needed to transmit radar data securely.
So they turned to the network of phone lines
that were already everywhere.
Phone lines were designed for people, though, not machines.
When we speak over a phone line, that data,
that's not very dense.
We can speak about 140 to 180 words per minute.
We can understand closer to 400 or more.
Now, if you convert that to bits, it's pretty low.
(OVER A PHONE LINE) But over the phone, there's static,
and there's noise, and it doesn't ever sound very good,
right?
Not to mention, every phone call runs through physical lines
that are sometimes more degraded,
or they're of higher quality or lower quality,
depending on where it is that you're
calling from and to an what kind of phone you're using.
All of that can affect the call, and it might not
be noticeable to us humans.
But it is to computers.
Modems use phone lines differently.
For example, people--
[ECHOING]
--you and I, can't talk and listen at the same time,
thanks to echoes.
But modems can.
And yet people can hear the patterns of speech,
[THROUGH STATIC] even through quite a lot of static or noise
whereas modems might have more trouble.
So all these weird sounds that your modem was making
is a way to make sure the modems know
what's going to be said, how to communicate,
who's communicating, and how they can do it back
and forth over this connection.
Luckily for us, Una [? Rossanin ?]
and Alex Madrigal broke this down for us.
You can find links to their stories
down in the description.
So let's say the blue person is the caller,
and the red person is the receiver.
This is what the modems were saying.
[PHONE DIALING SOUNDS]
Hello, this is a friendly modem.
Who are you?
Hi, this is a friendly blue modem.
Can we use information transfer?
Please turn off echo.
Also, I'm in the United States.
Looks like we can both transmit this basic data.
Yeah, we can.
OK.
Turn off echo and other things.
Here's my resume.
This is a landline, by the way.
Our resumes are very similar.
I can do some of this stuff as well and on digital
instead of analog.
I'm on a landline.
Here are my carry signals and power levels.
Samezies.
Let's test the line.
Let's test this line.
Great.
Looks like we can use a pretty good speed.
Try and keep your signal strong.
You got it.
[MODEM HISSING SOUNDS]
So at that point, the modems have introduced themselves.
They found out what speeds they can communicate at.
And they're ready to transmit their data.
All of this is called a handshake.
This handshake might trigger some nostalgia for you.
But did you notice that it might not
be the same as your handshake from when you were a kid?
Depending on the modem, the data speed, the line,
they're going to be a little different.
But they are very similar.
Over the years, clever engineers created
echo cancellation, phase shifting,
and other ways to send more data through voice lines.
But ultimately, the reason you heard all that static and beeps
and boops is because they had to translate those
sounds into whatever weird thing you were doing on Geo Cities
that night.
Once we stopped sharing phone lines with actual humans,
these noises weren't necessary anymore.
Your cell phone modem doesn't behave this way.
It does handshake with every cell tower and Wi-Fi device
that you come near.
But the protocols are based on digital signals
not on audible sounds.
I personally had a fun bout of nostalgia
reading Alex Madrigal's piece.
But you know me.
I couldn't just leave it there, right?
That's not why you watch this show.
So I looked up the Wi-Fi handshake too,
and it goes something like this.
Hello, welcome to Starbucks.
I am the Wi-Fi.
Here's a resume, key MAC address, drivers, and chip set.
OK, hello.
I am also a computer.
Here's my key and also the password
to access you and the MAC address and also my chip sets,
all of my resume, and all of my codes.
OK, hold up, calculating.
Cool.
Here's your session key.
Have fun.
Don't do anything that I wouldn't do on this Wi-Fi.
Thanks.
Obviously, this is oversimplifying
and a little silly.
But these protocols are built to make sure
that computers can talk with each other
consistently and carefully.
To be honest, when computers were first constructed,
they weren't designed to talk to each other.
At the basic chip and board level,
every computer is different.
Even your iPhone, which might look the same on the outside,
can have different chips running the stuff on the inside, not
to mention the phone lines, the amount
of interference, radiation, even micro surges in power
can all affect communication between you
and your chat rooms or Googles or whatever.
File done.
It's an incredible feat of engineering
that we can even get these binary hot boxes to converse
at all.
One last thing, special thanks to nerd fammer [? Keegan ?]
[? Gowhertz, ?] who answered my Twitter call for help on this
topic.
Keegan, you're a stara.
Thanks.
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more like a Grinchy kind of way.
Thanks for tuning in, everyone.
And as always, more research is needed.
Goodbye-- bye.