"One notices one gets old when the police stop you on the
highway - and tell you to drive faster."
HIGH SPEED MODEMS AND BBS WORLD
by Federico Bicini
(The best ever Italian ST NEWS
Yo freaks !
It's a long time ago that I felt like writing something in this
wonderful disk magazine - finally I've found the time and the
By the way, this doesn't mean that this article will be
published by the editors, but, if you are reading it seems that
they liked it! Thanks Richard and Stefan!
I've been very interested in the communication world for about
two years but it so happened that I bought my first modem just
four months ago - of course now I can say that it would have been
better for me if I had bought it earlier but, you know, everyone
knows what was better to do just after having done many wrong
things, or, at least, this tends to happen to me!
Anyway, when I got my new modem I didn't know anything about
bauds, transmission protocols, error correction, file compression
and so on. What I'd like to do in this article is to give you as
much informations as possible on the wonderful world of
communications. If you like this kind of thing something on
monthly basis could start on next ST NEWS issues - I mean
modem and BBS reviews and so on.
As I am surely not the major expert in the world if there is
someone out there who knows more than me, he is kindly invited to
start writing articles for the next ST NEWS issues!
So let's go!
It's clear that a modem (MOdulator-DEModulator) is used for
sending files/information/programs trough the telephone line and
it does this at certain speed! The higher the speed, the more
you'll have to shell out for the modem.
Modem speed is measured in Baud and just for the few who don't
know what a baud is the explanation follows here.
You know that a computer is a binary based machine and the
smallest memory unit is one bit, eight bits are a byte and 1024
bytes are 1K, so now you also know what it means that your Atari
ST has 512K or 1024 or more - easy, isn't it?
One baud is equal to one bit per second so when you put your
hands on a 300 bauds modem (really poor one!) this means that
your little metal box is able to transmit/receive at the speed of
300 bits for second. To make a clear example think you have to
send to a friend a text file of 1K (1024bytes/8192bits) it will
take to you 27.3 seconds to end the transmission. Quite a long
time, don't you think?
Fortunately 300 baud modems are close to disappearance from the
market since the electronic industry has made many steps ahead
and the prices are not so high even for faster modems.
And what about the standards in modems ? Actually about 100% of
the modems on the market use the standard Hayes-compatible
command set. Hayes is a company wich started making modems a long
time ago and its engineers designed this Hayes protocol wich
actually is to modems what MS-DOS is to a PC (Only better
Well, let's go on. As I told before, there are modems of just
about any speed starting at 300 bauds to 38,400. Up to 2,400
bauds there are thousands of companies wich produce good modems
at affordable prices and you'll surely find a shop in your city
that has this kind of hardware.
By the way, a 2,400 modem is also able to transmit/receive at
lower speeds - the standard ones usually being 300, 1,200 and
2,400. It will be priced at about US$ 250 or less but for this
price you'll get a simple modem without compression nor error
correction (I'll explain later what these things are).
At speeds higher than 2,400 bauds there are two different
standards - one is known as V.32 and the other as HST.
V.32 is by Hayes again, while HST is from US Robotics. The first
can transmit/receive at up to 9,600 bauds wich starts to be
quite a good speed (the same 1k text file now can be transmitted
in only 0.8 secs). The second standard uses a different kind of
data modulation through the phone line called "Trellis" (which
is, according to US Robotics, the best one).
HST modems can transmit/receive up to 38,400 at the best phone
line conditions, with both error correction and data compression.
By the way, error correction and data compression are available
at 2400 baud as well, so all modems can have them but if you are
searching for the fastest modem then you will have to buy an US
The two correction/compression protocols are MNP 1-4 (Error
correction) and V42-V42Bis (data compression); MNP level 5 is
also for data compression, but it has a lower efficency than
When two modems negotiate a connection they test the phone line
quality and try to connect at the best speed possible at that
moment using, if it exists, MNP and V42.
The latest HST modems also have ASL that is the short for
Automatic Speed Leveling, this means that the modem tries to
connect at the best speed possible and can increase/decrease the
speed according to the phone line conditions during the
Usually when you're using correction/compression protocols you
must set your modem port to a higher speed than the modem's one.
So if you want to use an HST at its maximum speed you must set
the RS232 to 38,400/19,200, depending on which computer you're
The Atari ST can be set to 19,200 while some Macintosh and Amiga
machines can reach 38,400.
The "real" speed of the modem trough the phone line is 14,400
baud, so the compression is used to compress the computer data
flow into a buffer which is then transmitted by the modem.
By the way, even if the "hardware" speed is 14,400 baud
effective speeds up to 38,400 baud can be reached with data
compression, even using an RS232 setting of 19,200 baud.
Recently a new standard has been added, called V32 bis. I
haven't yet tested it, so the only thing I can say is that it
should be an upgrade of the V32 which could let the modem connect
at 14,400/14,400 in both ways.
The HST connections are not 14,400/14,400, the modem
automatically assigns 14,400 to the major data flow and uses a
much lower speed (75 baud I think) for the error control, but
basically the V32bis should not be a very big improvement since
usually there is no need to use 14,400 in both ways, at least for
Well - what about the prices? They're different in every country
and as with most other stuff the USA ones are the cheapest, this
is due also to the fact that US Robotics is a USA company.
Usually V32 modems are priced almost the same as HST and often
also more, so I don't see any reason to buy a slower modem for a
bigger price, do you?
But let's speak about numbers. An HST DUAL modem, which has both
V32 and HST costs about US$ 1,000, but it's not so hard to find
one for US$ 800 to US$ 850 - so basically I'd like to say just
one thing: What are you waiting for? Buy one now!
This part of the article has been written two months after from
the part above and I've decided to add something else since
something has changed, expecially concerning the prices.
There are now two new models of modems out in the market of the
high speed transmision and exactly the new US ROBOTICS HST DUAL
STANDARD and the SUPRA range of FAX MODEMS.
SUPRA corporation is also a USA company like US ROBOTICS and it
is one of the best known worldwide.
There are two really interesting new SUPRA modems, the SUPRA FAX
MODEM V32 and the SUPRA FAX MODEM v32 bis. Both of them have the
capacity to send and receive fax directly from your computer
(using the right software) and of course they act like a normal
modem. The first one can handle speeds up to 9,600 baud, while
the second can reach 14,400 baud. Both have v42 bis and MNP 1-5
and also a new compression protocol MNP 10 which, in theory,
could give to the modem the possibility, in perfect line
conditions, to reach 58,600 bauds!
And guess what? SUPRA sells these nice pieces of hardware for
just US$ 399 and US$ 299 respectively for the V32 and the V32bis
versions - but I've already seen some USA shops that sell them at
US$ 305 and US$ 240.
I think that there is no more sense on buying old 2400 modems,
since the price gap between low and high speed is definitely
dead! No more excuses for not entering the wonderful world of
On the other side, US ROBOTICS has improved its top modem (the
HST DUAL STANDARD). It now features V32 bis, too, it's contained
in a smaller case than before and it has also been improved on
the HST side - the maximum speed through the line now being 16800
What more to say? I would just like to tell you what to buy:
Always buy the fastest modem possible, since a little bit more
spent on the modem means big savings on phone bills!
I'm still on the US ROBOTICS side myself, expecially now they
have a new model - since V32bis has been out for a while and I
think it will take about 1-2 years for it to be well spread in
If you want to be sure of your purchase and don't want to
complain on your money you should buy an HST DUAL (new version).
You won't have problems for at least 4 years.
I can only say that if you won't be satisfied with your HST DUAL
I will refund you all the money you've spent ! (Eh,eh!)
The text of the articles is identical to the originals like they appeared in old ST NEWS issues. Please take into consideration that the author(s) was (were) a lot younger and less responsible back then. So bad jokes, bad English, youthful arrogance, insults, bravura, over-crediting and tastelessness should be taken with at least a grain of salt. Any contact and/or payment information, as well as deadlines/release dates of any kind should be regarded as outdated. Due to the fact that these pages are not actually contained in an Atari executable here, references to scroll texts, featured demo screens and hidden articles may also be irrelevant.