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MegaDisc 24 (1991-10)(MegaDisc Digital Publishing)(AU)(Disk 2 of 2).zip
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MegaDisc 24 (1991-10)(MegaDisc Digital Publishing)(AU)(Disk 2 of 2).adf
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TELECOMMS
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Beginners_Comms
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Beginners_Comms
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Text File
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1991-09-26
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9KB
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237 lines
COMMUNICATIONS 101
AN INTRODUCTION TO TELECOMMUNICATING WITH A MODEM
By
Dave Freeman
Ed: Dave has provided us with a bunch of useful stuff this issue on
telecommunicating, as you'll see from the rest of the material in this
drawer, and there'll be more coming in future issues. Check out his BBS
(details below) if you want to see how they run.
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Have you ever wondered what this modem stuff is all about?
Would you like to get access to the latest public domain programs?
Would you like to be able to get a program without having to get the
whole disk full of stuff you don't want?
Do you like to play games against other computer users?
Do you want to get together with other computer owners and talk about
subjects that interest you?
All this and more will be discussed in this series of articles.
That's right, everything you ever wanted to know about communications
but were afraid to ask. In this issue I will just stick to the basics
of getting a modem and making it work.
What do you Need?
-----------------
The requirements for getting into the world of communications are
fairly small. This is what you will need for basic day to day use:
a. A Computer - You probably already have this.
b. A Phone - You probably have this also.
c. A Modem - I'll discuss this soon
d. A Cable - To connect it all.
The Modem:
----------
Just about any modem will do. There are a few things that you should
look for though. Any modem that you buy should have an Austel Approval
number on it somewhere. It is illegal to connect a non-Austel approved
modem to the phone line (it is not, however, illegal to sell one -
provided you advertise that it is not Austel Approved - isn't the law
wonderful?). The modem should also be a 'Hayes' Compatible. This means
that it will have certain standard commands and configurations built in.
There are some modems that do not include this. While they still work,
it is harder to get help in using them as you have to find someone that
is familiar with that particular modem and computer.
Speed
The main measure of a modem is its speed, i.e. speed of data
transfer. The most command term for this is Baud Rate. A mid-priced
modem will probably run at about 2400 baud, and sell for about $300 or
so. Given the price of 2400 baud modems I would not recommend that
anyone get a slower modem as you will very quickly want something faster
and will have great trouble selling a 1200 (or 300) baud modem.
If you are away from the larger cities then you may want to consider
getting something faster still. The most common speed up from 2400 is
9600 and prices start at about $900. From here on the sky is the limit
for price and options.
I have experience in Netcomm, Maestro and Dataplex modems - all of
which are Australian built and quite good quality. Most computer
retailers will be able to help with information on modems and prices.
The Cable:
----------
Unless you got your modem from an Amiga dealer the chances are that
the included cable will not be compatible with your computer. This is
because the Amiga has voltage on some of the pins of its serial port.
For those of us who still have an Amiga 1000 (with or without the
Phoenix Board) the dangerous pins are numbers 14, 21 and 23. For those
with any other Amiga, the ones to avoid are 9 and 10. Many serial
cables just have the full 25 connected up.
If your cable does not have moulded plugs then you can open them up
and disconnect the required pins at one end. Don't forget to shield
them from short circuits if you do this. The other option is to look
around for a 'bare' serial cable. The only pins that are needed for
serial communications are numbers 1 to 8 and pin 20. You can usually
find cables that are wired this way from a computer dealer.
A Program:
----------
Even when you have all this going you will still need a 'Terminal'
Program in order to use your modem. There are three main programs in
use for communications on the Amiga:
1. GPTerm - A Commercial Program (RRP about $100), latest version 4.56N
2. JRComm - A Shareware Program (US$50 to Register), version 1.02
3. NComm - A Public Domain Program, latest version 1.92
(See a separate review of these programs, and the PD ones can be
obtained from Megadisc's PD library - see the PD_UPDATE drawer).
Connecting It Up:
-----------------
OK, now for the meaty bit. Turn your computer off and connect your
modem to the serial port. Now turn it all back on (including the modem)
and start up your terminal program (whichever one you use).
You should now be able to communicate from your Amiga to the modem.
To test this you can simple type
AT <RETURN>
and you should get something like this on the next line
OK
Trouble-shooting
If you got something other than this (or nothing at all) then there
are a few things to check. First make sure that you have got your cable
right. Many of the problems that I have seen have been related to
cabling. If that is OK then check that you have FULL DUPLEX selected.
Also, make sure that whatever handshaking you have selected in your
program is supported by the modem (read the manual for the modem for
this). All these options should be in pull down menus.
If you are still having trouble at this stage then I would suggest
that you get in touch with someone who has more experience. There are
so many things that could be wrong that it would take more space than I
have to deal with them all.
Using It:
---------
Now you get the chance to use all this stuff! Before leaping in to
making the call, there are a few things that you should check out first.
You will need the phone number of a Bulletin Board Service (BBS) to
call. You will also need some information about that BBS. This
information is used to configure your computer and modem so that you can
talk to the BBS properly. The information you need is:
Highest Common Baud Rate - What is the fastest speed at which you can
both operate?
Serial Configuration - Normally this will be 8 data bits, 1 stop bit and
no parity (once again these should be in pull down menus).
Operating hours - some BBSs run 24hours per day. Others only at certain
times. It is always a good idea to make sure that you will be calling
when there will be a modem at the other end to answer.
As an Example, my BBS operates at speeds of up to 9600 Baud with 8
data bits, 1 stop bit and no parity. It is on-line 24 hours per day.
If you had a 2400 baud modem you would use that. It is assumed that a
listed baud rate is the fastest available and that slower speeds can
also be used.
Most terminal programs will let you save your commonly called numbers
in a 'phone book' for ready use. I will discuss this in a later
article. For now, let's just use the keyboard to make a call. This
will give you a better idea of what happens when you later just select a
phone book entry.
Once you have your Terminal program set up with the baud rate etc (all
can be found on pull down menus). Type the following:
ATDT070531199 <RETURN>
This will make your call for you. Now let's break this down and see
what we just did...
AT - Attention Modem, I want you to do something. This 'AT' command is
the start of most commands that you will issue and alerts the modem
to an impending command.
D - Dial out. Tells the modem that you are making a call.
T - Use Tones to make the call. (If you only have a pulse dial phone
then you can use 'P' instead here). If your phone has buttons
instead of a rotary dial then you are probably tone dial.
070531199 - This is the number that you want to dial. Substitute it for
the number of the BBS that you want to call. Include any STD
code that you may need. It is not necessary to put any sort
of spaces or brackets in here. Indeed, some characters like
commas will be interpreted as a 2 second pause.
And there you have it. You have just made your first call. Next time
we will take up from here with what to do when you reach a BBS for the
first time. What (and what not) to do.
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Any questions, comments, queries, gifts or donations can be directed
to me as follows:
To My BBS: 'The Ice Cave' Phone (070)53-1199 24 hours a day at speeds
up to 9600 baud.
Or via Megadisc.
(Oh yeah, the '070' is Cairns in Queensland - and it really is nice up
here at this time of year).
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