[comp.sys.mac.hardware] 2400 baud modems

pete@titan.rice.edu (Pete Keleher) (02/13/90)

A recent ad in MacWorld for "MacProducts USA" quoted a $99 price for a
100% Hayes-compatible modem called "MagicModem".  I'm skeptical, anyone
know anything about this beast?

--

Pete Keleher						pete@titan.rice.edu

clarson@ux.acs.umn.edu (Chaz Larson) (02/13/90)

In article <PETE.90Feb12121557@titan.rice.edu> pete@titan.rice.edu (Pete Keleher) writes:
>
>A recent ad in MacWorld for "MacProducts USA" quoted a $99 price for a
>100% Hayes-compatible modem called "MagicModem".  I'm skeptical, anyone
>know anything about this beast?

I have one of these, with the nameplate "ZOOM" on it.  I urge you to stay
clear.  Spend the extra $80 for a Practical Peripherals PP2400SA; it has
MNP-5 error-correction and is much more reliable.  My ZOOM has continual
problems connecting if there is even someone in the metropolitan area
thinking the words "line noise."

<chaz>

BTW, I have no connection with Practical Peripherals, except as a friend
of many people who are happy with their PP2400SA's.  ATI makes a similar
modem at a similar price [ATI 2400etc]


-- 
----------------------------------------------------------------------
                 Chaz Larson - clarson@ux.acs.umn.edu
            "Hey, I'm no Jack Kennedy..." - Flaming Carrot
----------------------------------------------------------------------

jeff@eniac.seas.upenn.edu (Jeff White) (02/13/90)

In article <PETE.90Feb12121557@titan.rice.edu> pete@titan.rice.edu (Pete Keleher) writes:
>
>A recent ad in MacWorld for "MacProducts USA" quoted a $99 price for a
>100% Hayes-compatible modem called "MagicModem".  I'm skeptical, anyone
>know anything about this beast?

  Only that from the picture the ad shows of it, it looks a lot like the
Zoom 2400 baud external modem, which sells for $129.  The Zoom comes with a
7 yr warrantee,  certainly worth the extra $30, IMHO.

						Jeff White
						University of Pennsylvania
						jeff@eniac.seas.upenn.edu

bmh@cunixd.cc.columbia.edu (Brian M Hoffman) (02/13/90)

In article <PETE.90Feb12121557@titan.rice.edu> pete@titan.rice.edu (Pete Keleher) writes:
>
>A recent ad in MacWorld for "MacProducts USA" quoted a $99 price for a
>100% Hayes-compatible modem called "MagicModem".  I'm skeptical, anyone
>know anything about this beast?


I've never heard of a 'MagicModem,' but the price sounds about right to
me.  With the coming rise of 9600 and faster, the price of 2400's are
really dropping.  A brand I can recommend is Practical Periphrials.  PP's
modems are priced right and come with a 5 year guarentee.


Brian


Disclaimer:  I say whatever I want, so there.

james@utastro.UUCP (James McCartney) (02/15/90)

> In article <PETE.90Feb12121557@titan.rice.edu> pete@titan.rice.edu (Pete Keleher) writes:
> >
> >A recent ad in MacWorld for "MacProducts USA" quoted a $99 price for a
> >100% Hayes-compatible modem called "MagicModem".  I'm skeptical, anyone
> >know anything about this beast?

   MacProducts is right down the street from here. I bought a Magic30 hard
disk from them years ago. I never got support software that they promised
would come with it. They are a sleazoid operation if I ever saw one.
 --- James McCartney

jeff@tc.fluke.COM (Jeff Stearns) (02/15/90)

In article <PETE.90Feb12121557@titan.rice.edu> pete@titan.rice.edu (Pete Keleher) writes:
>
>A recent ad in MacWorld for "MacProducts USA" quoted a $99 price for a
>100% Hayes-compatible modem called "MagicModem".  I'm skeptical, anyone
>know anything about this beast?
>
>--
>
>Pete Keleher						pete@titan.rice.edu

I was skeptical.  I bought one.  It was delivered quickly.

The speaker is cruddy, and the case isn't as robust as it
could be, but it's perfectly adequate for home use.

It has a couple of nifty "switches" that are all set via
software; there are no hardware switches at all.
It claims to be Hayes-compatible; I see no reason to doubt that.

It has a trimpot to adjust for unusual line impedances.
I had no need to fiddle with it.

It worked flawlessly on local and short long-distance calls,
transferring 1**6 characters without error.
I haven't tried it on any longer-distance calls.

I would buy another without hesitation.
-- 
    Jeff Stearns        John Fluke Mfg. Co, Inc.               (206) 356-5064
    jeff@tc.fluke.COM   {uw-beaver,microsoft,sun}!fluke!jeff

carlo@merlin.cvs.rochester.edu (Carlo Tiana) (02/16/90)

In article <14938@fluke.COM> jeff@tc.fluke.COM (Jeff Stearns) writes:
> [lots of good things about modem]
>It worked flawlessly on local and short long-distance calls,
>transferring 1**6 characters without error.
              ^^^^^^^^^^^^^^^

I would not base my purchase on this recommendation... ;-) ;-)
Sorry, I could not resist!
Carlo.

carlo@cvs.rochester.edu

6600bike@hub.UUCP (Puneet Pasrich) (02/16/90)

I hope this is the right place to post this...
I have a 2400 baud modem, but I don't _really_ know what that means.
Could someone fill me in on how to convert baud to data transfer?
Something like, how long will it take to receive a 1meg file, assuming
no data loss, no packet problems, etc. at 2400?  What's the "formula"?
 
Thanks!
  ___________________________________________________________
  |Puneet Pasrich  |  Internet:  6600bike@ucsbuxa.ucsb.edu  |
  |Karate Kid      |  Bitnet:    6600bike@ucsbuxa.bitnet    |
  |'Just do it!'   |                                        |

mjkobb@mit-amt.MEDIA.MIT.EDU (Michael J Kobb) (02/16/90)

In article <3967@hub.UUCP> 6600bike@hub.UUCP (Puneet Pasrich) writes:
>I hope this is the right place to post this...
>I have a 2400 baud modem, but I don't _really_ know what that means.
>Could someone fill me in on how to convert baud to data transfer?
>Something like, how long will it take to receive a 1meg file, assuming
>no data loss, no packet problems, etc. at 2400?  What's the "formula"?

  This question is more complicated than it seems on the surface.  "baud" as I
understand it, relates to the frequency with which the carrier signal of the
modem is modulated.  Since phone lines have a limited frequency range, there
is a limit to how high you can go with baud rates (and 2400 is getting up
there, I believe, especially since you have to fit two signals in; I believe
that 2400 actually requires the modems to filter their own signal out to find
the other modem's, but I may be confusing that with 9600).  For speeds <=2400
baud, it's fairly safe to assume ~1bit/baud, so a 2400 baud modem does
~2400bps on a really good day.  Using ZTerm, I usually get a K every 4 seconds
or so, and ZTerm is claiming 96% efficiency, so that means that, roughly
speaking, it would take about 4096 seconds, or ~68 minutes to download a
megabyte.

  It is possible to increase the bps on a given baud rate, for example, using
compression algorithms like MNP5 (yay, Paul!), which can give an effective
throughput of 4800bps on a 2400 baud signal.  You can also do weird things
with the encoding of the data streams to get 9600 and 19200 bps rates out of a
normal phone line, and I understand that MNP6(?) is now able to push nearly
38400bps on a normal phone line (I want two of these, and X for my Mac, and
I'll be a happy person!)

  I hope that this helps, and I entreat the more knowledeable out there to
correct me (here, please) if I've screwed up somewhere...

--Mike

magik@chinet.chi.il.us (Ben Liberman) (02/17/90)

In article <3967@hub.UUCP> 6600bike@hub.UUCP (Puneet Pasrich) writes:
>Could someone fill me in on how to convert baud to data transfer?
>Something like, how long will it take to receive a 1meg file, assuming
>no data loss, no packet problems, etc. at 2400?  What's the "formula"?

Baud = bits/second.  Usually (8 bits/char., no parity bit, 1 stop bit, 1 start
bit) there are 10 bits in every character sent, so

    2400 baud = 240 characters per second

    1 megabyte = 1,048,576 bytes = 4,369 seconds at 2400 baud = 72 min. 50 sec.


-- 
	------------    ------------   ----------------------
	Ben Liberman    USENET         magik@chinet.chi.il.us
	                GEnie,Delphi   MAGIK

jmunkki@kampi.hut.fi (Juri Munkki) (02/18/90)

In his article magik@chinet.chi.il.us (Ben Liberman) writes:
>In article <3967@hub.UUCP> 6600bike@hub.UUCP (Puneet Pasrich) writes:
>>Could someone fill me in on how to convert baud to data transfer?
>>Something like, how long will it take to receive a 1meg file, assuming
>>no data loss, no packet problems, etc. at 2400?  What's the "formula"?
>
>Baud = bits/second.  Usually (8 bits/char., no parity bit, 1 stop bit, 1 start
>bit) there are 10 bits in every character sent, so
>
>    2400 baud = 240 characters per second
>
>    1 megabyte = 1,048,576 bytes = 4,369 seconds at 2400 baud = 72 min. 50 sec.

Actually bauds measure the modulation rate and can be totally different
from the bits per second (bps) data transfer rate. Older modems usually
transfer one bit at a time so it's quite common to say that baud=bps.
Faster modems transfer multiple bits at a time so the baud rate doesn't
say much about the actual transfer rate.

Then you have to take into account even newer modems that pack data and
correct errors. For binary data the transfer rate can be quite different
than what you get with just 7 bit ASCII.

The third thing that you have to account for is the speed of the protocol
that you are using. Plain kermit or xmodem waste a lot of time because the
data length/packet length ratio is quite low. I recommend using ZMODEM
where you can get about 90% efficiency on an error-correcting modem.

Basically what I'm saying is that even if someone says that a modem is
9600 baud, that person doesn't really mean baud, but bps unless the modem
uses a very special phone line that can carry that much bandwidth. You
can then merrily divide this rate by 10 to get an approximation of how
fast characters might be transfered. For actual file transfers, you need
to account for packet overhead. It's quite safe to add 10%, since most
protocols aren't all that optimal anyway. If you are using an old kermit
implementation and tranfering a binary file, expect to double the time.

The above is of course nit-picking and probably doesn't interest you if
you aren't already interested in splitting hairs. :-)

_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
|     Juri Munkki jmunkki@hut.fi  jmunkki@fingate.bitnet        I Want   Ne   |
|     Helsinki University of Technology Computing Centre        My Own   XT   |
^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^

george@swbatl.UUCP (6544) (02/18/90)

In article <1990Feb17.130612.1828@chinet.chi.il.us> magik@chinet.chi.il.us (Ben Liberman) writes:
>Baud = bits/second. 

Just to clear up a common misconception:
BAUD IS NOT ALWAYS THE SAME AS BITS PER SECOND!

The following is paraphrased from the IEEE Standard Dictionary
of Electrical and Electronic Terms:

"The term ''baud'' defines the signaling speed, that is, keying 
rate of the modem.  The signaling speed in baud is equal to the
reciprocal of the shortest element duration in seconds to be
transmitted....The bit rate and baud are not synonomous and shall
not be interchanged in usage.  Preferred usage is bit rate, with
baud used only when the details of a communication modem or channel
are specified."

For example:
My modem is 2400 bps (bits per second), but its signaling rate is
1200 baud.  How can this be?  Two bits of information are encoded
into each signaling element.

-- 
   /   George D. Nincehelser           \  uunet!swbatl!george       \
  / /   Southwestern Bell Telephone     \  Phone: (314) 235-6544     \
 / / /   Advanced Technology Laboratory  \  Fax:  (314) 235-5797      \
/ / / /\  1010 Pine, St. Louis, MO 63101  \  de asini umbra disceptare \

rcfische@polyslo.CalPoly.EDU (Raymond C. Fischer) (02/18/90)

In article <3967@hub.UUCP> 6600bike@hub.UUCP (Puneet Pasrich) writes:
>I hope this is the right place to post this...
>I have a 2400 baud modem, but I don't _really_ know what that means.
>Could someone fill me in on how to convert baud to data transfer?
>Something like, how long will it take to receive a 1meg file, assuming
>no data loss, no packet problems, etc. at 2400?  What's the "formula"?

Despite postings that indicate otherwise, baud is NOT synonymous with
bits-per-second.  But since the two are often confused, you usually
can assume bps when reading baud.

Baud indicates the number of signal changes per second.  With the old
110 bps modems, a high pitched tone indicated a 1 bit and a low pitched
tone indicated a zero bit.  (this is called FSK for frequency shift keying).
Thus, 110 baud = 110 bps = 10 characters per second (since each character
is sent as 11 bits).

New modems are fancier.  Using a combination of PSK (phase shift keying)
and ASK (amplitude shift keying) a 2400 bps modem manages to encode 4 bits
into each signal change.  Thus, with a signalling rate of 600 baud, the
modem is able to send 2400 bps.  1200 bps modems also work at 600 baud,
but are not as clever about encoding bits, using only PSK to encode 2 bits
per baud.

Usually characters are sent at 10 bits/character (1 start, 8 data, 1 stop)
and so at 2400 bps you transfer 240 characters per second.  Doing some
rounding, this means about 1K bytes in 4 seconds, or about 7 minutes to
transfer 100k bytes, or roughly 6 seconds to fill a 24x80 screen full of
text.

Answer your question?

Ray Fischer
rcfische@polyslo.calpoly.edu

bond@aerospace.aero.org (Walt Bond) (08/19/90)

In article <STUCKI.90Aug16133549@neuron.cis.ohio-state.edu> stucki@neuron.cis.ohio-state.edu (David J Stucki) writes:
>Does anyone have good or bad or otherwise recommendations for Zoom
>Technologies' 2400 baud modem (with sendfax)?
>
>thanks in advance...
>
>dave...

Recently had my "Maxon 2400" go belly up, and they want $55 to fix it.
Damn thing only had a 90-day warranty, and now I know why. Anyone want
to buy it for, say, $35? It still works if you let it warm up for a 
while, sometimes.

I see that for $69 I can get what appears to be an OEM version of the
Zoom 2400 from 800-MAC-STUF. 2yr warranty. This sounds like the ticket,
but wait...

The Zoom 2400 sendfax modem is only $119 from several sources.  I decide to
try one from Software-That-Fits since they have free tech support and a
30-day return policy.  7yr warranty.  800-972-3018.  

It shows up in a couple days, works just fine as a Hayes-compatible
data modem (am using it right now) with Versaterm. But there are
problems...

   Software with the modem is "Quicklink II Fax" version 1.0.2, created
20 April 1990. This is a basic comm program with TTY, VT100/102/52
emulation and X/Ymodem and Kermit/"SuperKermit" (whatever SuperKermit
is, and they don't say) file xfer. Has a scrollback buffer. This same
program is supposed to send faxes, but they must be either simple text,
Pict, MacPaint, or TIFF files.

   Not a bad effort considering the price, but the VT102 emulator has
problems. For example, when talking to a VAX/VMS host running EDT,
deleting a line in the buffer didn't scroll the text up to fill the gap
as it should.

   I hit real problems when trying the FAX feature. This from a MacIIcx.
Either the machine would lock up with no message, or Quicklink would
complain that it can't find the modem. After some fiddling I give up and
call Zoom's 800-number, but they refer me to their tech support line
(not toll-free). So we try Software That Fits tech support. They just
happened to be trying to get a Zoom sendfax to work and had been having
problems also.
   But... next day they said they had gotten it to work per the instructions
and that another customer who had been having problems managed to send
a fax also. He said Zoom said that this was sensitive to the serial cable
pinout and gave me the "correct" pinout. I check my cable and sure enough,
it isn't exactly as he said it should be, even though it has worked fine
with a data modem (and with the Zoom).
   At this point I'm undecided whether to bother getting a new cable
or not. Even if it does work, the Quicklink II software isn't very
wonderful - hanging the machine is not nice, no matter what sort of
cable might be there. You can't simply take a MacWrite file and fax
it either.

Anyone else tried this puppy?

The next-most-interesting modem is a new one from Global Village (see P144 of
7 August 1990 MacWeek), 800-736-4821.  $150 gets you a "Teleport" modem that
plugs into the ADB, and uses the ADB for both power and data transfer,
without affecting keyboard or mouse response, they say.  Includes a sendfax
option that may be $60 or free, depending on whether or not they decide to
extend a special offer.  The fax software isn't available yet, but the modems
are.  5-yr warranty, 30-day return option.  Modem is Hayes compatible and has
MNP-5.  Person I talked to there sounded knowledgable, but has been nearly a
week and I haven't gotten the printed info I requested yet.  A CDEV will
remap one of the normal serial ports into this modem.  Or if you have COMM-
toolbox running, this is another available serial device.  

(posted for a friend, but you can reply here. we have no affiliation with
any of the above except as potential or real customers of uncertain
satisfaction.)

ts@cup.portal.com (Tim W Smith) (08/20/90)

$150 for 2400 bps (not baud, dammit!) + $60 for the ability to send
a fax is $210.  This doesn't strike me as a good deal.

Prometheus has a 2400 bps (not baud, dammit!) + send FAX modem that
I've seen in stores for $230, and it comes with good software
(Backfax and Macknowledge), and Prometheus is a well known company
in the modem world.  I sold mine, but not because of any flaws in
the product.  Rather, I decided that I wanted something that would
receive also.

For $280 mail order, there is the DoveFAX Desktop, which can also
receive FAX.  Also, the DoveFAX can operate in the background,
and the FAX is 9600 bps, unlike many of the send only FAX modems,
which are 4800.  I've had one for a few days, and it seems to work
fine.

					Tim Smith

bond@aerospace.aero.org (Walt Bond) (08/21/90)

In article <33015@cup.portal.com> ts@cup.portal.com (Tim W Smith) writes:
>$150 for 2400 bps (not baud, dammit!) + $60 for the ability to send
>a fax is $210.  This doesn't strike me as a good deal.

As you stated it, perhaps not. However, there is added value in the
smaller footprint, no external power cube to mess with, built-in 
MNP Level 5, and possibly included free sendfax software (if their intro
offer is extended) that looks like a chooser-selectable printer (and is 
thus compatible with most any Mac software, unlike Zoom/Quicklink).

BTW, the problem with the Zoom/Quicklink on MacIIcx did turn out to be
the cable. Thing will send faxes, but the user interface and compatibility
with Mac applications (can only send plain text (ASCII), TIFF, or PICT
files) leave much to be desired.