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CHAPTER.7
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1993-07-21
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CHAPTER 7
THE MODEM
As was mentioned earlier, there is a "card" that can be plugged
into the motherboard which has two phone jacks built into it.
This is called a modem. And it allows two computers to talk with
each other by sending digital electronic impulses through the
phone lines. It is also possible to transfer the data
in files digitially as well. This is called DOWNLOADING if you
are getting the information from the remote computer and
collecting it in a directory on your own computer; it is called
UPLOADING if you are sending the information from a file in your
upload directory to the download directory of the remote
computer! The speed at which the transfers can take place is
very varied from 300 bps baud to 14.4K and even higher than that.
BPS means bits per second or how many times per second switching
off and on can occur thus transferring the information. These
days the 2400 bps baud rate is the standard, while many users
have the 9600 baud and quite a few are purchasing the 14.4K or
thousand bps rate, which is a very fast rate of transmission.
Running a remote program at 14.4K rate can almost seem as though
the program was being run locally or not through the phone lines
at all. The transfer is just about instantaneous. Most like in
the future the baud rates will be much higher than they are now
to insure that remote programs ie. on bbses etc, run as if they
were being run on the host computer. This means that transfer
time for downloading will be next to instantaneous as well.
Just a note here on some terminology:
1 byte = 8 contiguous bits of information
1000 bytes = kilobyte or K = 1024 bytes
1000 Kilobytes = 1 megabyte or M = 1,048 kilobytes
You will hear terms like 120 MEG Hard Drive: that means the
hard disk in the computer cabinet can hold approx 120 Million
characters of information, that's a lot of typing! Or, a
file to be transferred has 145 K or 145 kilobytes. It
takes about 10 minutes to download 100K at 2400 baud. So 145K
would take about 14.5 minutes. At 14.4 K however it would
only take 1 minute to download that same file!
So who do I call with my modem? Well it depends on what you
want to do! You could call in Interpersonal Computer Service
like PRODIGY. And for a relatively low monthly rate you could
access a lot of information which includes the latest news,
weather, sports, stock market quotes, shopping news, on-line
banking and shopping and many clubs with bulletin boards where
users from across the country call in and leave messages for
one another! The graphics are very good and the color is
spectacular. A good investment in modem use!
There is also E-mail.... where you can call and get messages
left for you. Like your own answering service. You read the
messages and then answer them and the answerees get the
replies in their E-Mail. E-Mail means ELECTRONIC MAIL.
There is also the BULLETIN BOARD SYSTEM or BBS. This is a
smaller edition of PRODIGY...... the same types of stuff but
much less sophisticated, but a great source of information.
A bulletin board system has 5 major areas. A message center,
a files center, a bulletin center and a questionnaire center
and most have a doors center where auxiliary programs are run
which generally are games you can play on-line..... some of
these have great graphics and are a lot of fun to play.
BBSes are relatively easy to set up and in larger metropolitan
areas there are a great number of them to choose from. Some
are totally free, meaning there is no charge to use them. Some
are partially free and partially subscriber. And some are
totally pay boards. The rates are usually relatively low for
the service and features you get for a year's time. An
example of a GENERAL BBS for the whole family is TOWN SQUARE
BBS in Norfolk, VA. 804-625-0728.
Phone lines can cause some interference sometimes and the
result is LINE NOISE or garbled symbols strewn at random on
the screen. Sometimes if a great many symbols are thrown on
the screen at one time it could mean that the connection
itself was broken as when someone in your house picks up an
extension phone...even for a second. This can be disastrous
if you are downloading a file for example..... it can really
screw up the transmission, and if you are in the middle of a
big (amount of K) file you could really get a little angry! or
a LOT angry! The real moral of the story is GET A DEDICATED
line for your modem use only ..... that is if you plan on
spending a LOT of time on the modem .... It is unfair to ask
your whole family to stay off the phone for hours at a time.
Call waiting is NOT the answer to that either, for a call
coming in on call waiting, not only will give you line noise,
but may even throw you off the line completely ... called
DROPPING CARRIER. Sysops (Operators of BBSs don't like it
when you DROP CARRIER in the middle of a program! - could
screw up his board! - then you'd really have a problem!) So
DISCONNECT call waiting when calling out on a modem .....
there is a way to do that temporarily while you use the modem,
and then have it come back on when you are finished.
Just another word about the "speedy" modem. The actual
transmission speed depends on what the remote (not your
computer) computer can put out, not yours. If you have a
28.8K modem and the board you call only has a 2400 baud you
ain't gonna get more than 2400 baud out of it! But if the
board has a 14.4K baud rate modem and so do you, then you are
in business ... you can upload and download and operate the
program in general at a really high rate of speed. For a
while 1200 baud was the standard, then it was 2400 baud a
couple of years ago, now it is a 9600, and shortly it will be
14.4K, until the next generation of computer, then who knows!?
LOCKING: sometimes in modem use and sometimes not, you will
run across a situation where the program LOCKS-UP...... which
means that no more keyboard commands can be entered at all and
the action on the screen has therefore ceased. This can
happen for a number of reasons. Should this happen to you ...
it is most likely NOT a crisis situaiton (if you have been
saving your information every few minutes - you will only lose
the data entered since the last save)..... the only way to
"get the thing to "GO" again is to RESET it! That is hit the
RESET BUTTON which will re-boot the computer all over again!
(Sometimes a warm boot will accopmplish the same thing: that
means hitting simultaneously the CTRL-ALT-DELETE keys.
To get back to where you were before you would then need to
restart the program you were in and open the file you were
working on.