- PC HARDWARE -

Shown below is an Intel 56K internal modem that can be bought on-line at `Justmodem' for only $9.00!  I have had super luck with this modem in terms of connect speed and stability - and it has become my first choice of modems for new systems I'm building (including my own).  For `dial-up' internet service, or faxing something down the street from your PC, you can't beat this card!!

For a little background, the word “Modem” is an acronym for the term “modulator/demodulator”.  To “modulate” something means (in one sense) to change its’ form.  In telephone transmission, a `modem’ takes a digital signal (1’s and 0’s) input from a computer (or other digital source) and converts it by a modulation process to an analog signal output (like your voice) suitable for sending over a telephone line to a receive modem.  The receive modem then converts it back into a digital signal by a reverse (de-modulation) process.

The other kind of modem is the one used for hi-speed internet access and is used with both cable and DSL services.  These are usually provided free by your internet service provider (ISP), but to use them you need an Ethernet (or USB) interface on your computer.   If you have more than one computer in your home, you will also need what is known as a 'router' which will connect several computers to one modem.  The unit above is actually a combination modem and router.

I do not recommend you go out and buy your own modem before you sign up with an ISP.  Like I said, they are usually provided free - and, also, they are usually programmed remotely from the ISP location and are unique to the providers particular software protocol setup.

Dial-up Modem speed depends on the type of modulation process used to impose the digital information on the analog carrier (the signal that carries the information “piggy-back” to another modem).  To try to keep it simple, a telephone circuit, because of bandwidth limitations, will only transmit a signal up to around 3,000 cycles-per-second (Hz).  All modems today use a transmission carrier signal of 2,400 Hz (within the 3KHz bounds) to transport data of rates of up to 56,000 bits-per-second (BPS).  The first “high-speed” modems could only carry one data-bit for each Hz of signal which gave us a 2,400 Baud modem - but today they can get 24 bits/Hz which adds up to the 56 KBPS (the term “Baud” is a misnomer above 2,400 BPS - but that is another story).   Speed means a lot in today’s world because the size of data files being transferred (millions of bits) that can only move at so many bits-per-second down a pair of telephone wires - and seconds on telephone lines cost money.  The bad news about sending data at this rate is that it is much more vulnerable to errors caused by telephone noise.

Cable/DSL Modem speed starts about ten times the speed of the fastest dial-up modem and goes up.  Goes WAY up!  It is not the modem itself, however, that makes the service so fast - it is the providers Internet connect speed.  I would like to also say here that connect speed is usually defined in terms of 'upload' speed and 'download' speed.  Upload speed plays a part when you are updating your web site - and download when you are logging onto a site or updating your computer software.  Typically, download speed is around 5 times as fast as upload speed (don't ask me why!).