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how my very first conection worked?





D'Artagnan
or how the hell my modem works? i know i know it may sound stupid at first, but i think most people (including many IT professionals ) just accept the fact that their connections are working and go on,

I can live no longer with such a question!!!
i know how DNS works, how HTTP Works, how IP works, what i want to know is.
How in heaven my modem was able to conect my computer to the internet in the first place, how by pluging my modem in my computer and in my telephone it was able to connect me to the internet?
ocalhoun
'Modem' is an acronym for "Modulator/Demodulator".

What it does is simply convert one type of signal to another. (by modulation*)
Your computer uses digital signals to communicate, but the phone line (of that time) was only able to carry analog (audio) signals. The modem's job was to convert the computer's digital signals to an analog audio signal that could travel across the phone lines.
At the other end of the line, at your ISP, there was another modem that did the opposite; it converted the analog audio signal from the telephone line back to a digital signal that could be routed through the internet.

Today's DSL, cable, and fiber modems do basically the same thing; the only difference is what kind of signal they convert the computer's signals into for transmission. (Different frequency digital, RF frequency analog, and light pulses, respectively.)

*Modulation is the process of adding an 'intelligence signal' to a 'carrier wave'. In the case of an old telephone modem, the carrier wave was an analog audio signal. This signal was combined with the digital signals from the computer to produce a modulated carrier wave (the modem noise). At the other end, the carrier wave was removed (demodulated), leaving only the intelligence signal (the digital signals from your computer).
What (one type of) modulation looks like:
Denvis
ocalhoun wrote:
'Modem' is an acronym for "Modulator/Demodulator".

What it does is simply convert one type of signal to another. (by modulation*)
Your computer uses digital signals to communicate, but the phone line (of that time) was only able to carry analog (audio) signals. The modem's job was to convert the computer's digital signals to an analog audio signal that could travel across the phone lines.
At the other end of the line, at your ISP, there was another modem that did the opposite; it converted the analog audio signal from the telephone line back to a digital signal that could be routed through the internet.

Today's DSL, cable, and fiber modems do basically the same thing; the only difference is what kind of signal they convert the computer's signals into for transmission. (Different frequency digital, RF frequency analog, and light pulses, respectively.)

*Modulation is the process of adding an 'intelligence signal' to a 'carrier wave'. In the case of an old telephone modem, the carrier wave was an analog audio signal. This signal was combined with the digital signals from the computer to produce a modulated carrier wave (the modem noise). At the other end, the carrier wave was removed (demodulated), leaving only the intelligence signal (the digital signals from your computer).
What (one type of) modulation looks like:


Oh wow! Very nice, basic yet detailed information on how a modem works. I actually learnt this a couple years back in high school I think it was in grade 9. This actually refreshed my memory on a lot of other topics that were associated with the communication between devices within networks.
Flakky
ocalhoun wrote:
'Modem' is an acronym for "Modulator/Demodulator".

What it does is simply convert one type of signal to another. (by modulation*)
Your computer uses digital signals to communicate, but the phone line (of that time) was only able to carry analog (audio) signals. The modem's job was to convert the computer's digital signals to an analog audio signal that could travel across the phone lines.
At the other end of the line, at your ISP, there was another modem that did the opposite; it converted the analog audio signal from the telephone line back to a digital signal that could be routed through the internet.

Today's DSL, cable, and fiber modems do basically the same thing; the only difference is what kind of signal they convert the computer's signals into for transmission. (Different frequency digital, RF frequency analog, and light pulses, respectively.)

*Modulation is the process of adding an 'intelligence signal' to a 'carrier wave'. In the case of an old telephone modem, the carrier wave was an analog audio signal. This signal was combined with the digital signals from the computer to produce a modulated carrier wave (the modem noise). At the other end, the carrier wave was removed (demodulated), leaving only the intelligence signal (the digital signals from your computer).
What (one type of) modulation looks like:

I'm having a bad connection lately so I had to get to know our home network setup. I did not immediately understand how our network works but soon realized how it did. One question that did raise was how can TV, radio and internet work on one cable, get split and go to the particular device with no problems?
ocalhoun
Flakky wrote:
One question that did raise was how can TV, radio and internet work on one cable, get split and go to the particular device with no problems?

Enter: the wonderful world of multiplexing.

Multiplexing is the process of putting more than one signal on a single line. (and then separating them later.)
There are several types:
-Time division - the different signals take turns using the line. Trunk lines in a computer network work this way, as do some phone lines.
-Frequency division - each signal is modulated, and then transmitted, with a different frequency carrier wave. By using a filter at the receiving end, the unwanted frequencies can be eliminated, leaving only the one you're interested in. I suspect this is how the cable company does it in your case.
rockpan
all internet traffic are voltage waves on the line...
ocalhoun
rockpan wrote:
all internet traffic are voltage waves on the line...

False.

A large portion of it is light waves on fiber optic lines.
(And the connection I'm using is radio waves sent back and forth to a satellite.)
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