From: Adam.Frix@p18.f20.n226.z1.FIDONET.ORG (Adam Frix)
Newsgroups: comp.dcom.modems
Subject: Re: Supra V.32bis (Disappointment)
Date: Fri, 10 Apr 92 01:00:10 EST
Organization: FidoNet node 1:226/20.18 - cmhGate UF Gateway, Columbus OH


dali@milton.u.washington.edu (David A. Lee) writes:

DAL> In article <1992Apr7.001144.27864@jato.jpl.nasa.gov>
jack@jato.jpl.nasa.gov 
DAL> (Jack Kobzeff) writes: > >I'll assume that you have a hardware 
DAL> handshake cable from Mac to modem. The >si can do HWH, but 
DAL> some of the cheaper or older Mac's can't. > >Jack Kobzeff 
DAL> (jack@jato.jpl.nasa.gov) 
DAL> So you mean that we humble Mac Plus users can't get 57000 
DAL> baud on a Supra or similiar modem? What is the top speed a 
DAL> Plus' serial port can take??

The Mac Plus can handle 57,600 baud just fine.  That's its top speed, and the
top speed for all Macs so far.  Many older modems, with no real need to go
that high, don't support that DTE-DCE speed.  Many newer ones are beginning
to.

Further, the Supra tech was wrong when he said that the Mac can't handle above
19,200 baud from computer to modem.  Either he's misinformed like some people
here (and most people in the PC world), or something.  I don't have a bit of a
problem with 38,400 baud between my Plus and my USR Courier HST, using the
proper cable, of course.  (A hint to save everyone a ton of time:  given the
Mac serial port makeup, and given a Mac hardware handshake cable, you must set
your modem to ignore DTR.  This is a DIP switch in some cases, software in
others, and some modems can do it both ways.)  There's absolutely no reason
why any Mac should have any problems dealing with the new Supras, unless the
problem is on Supra's end.  But I guess this is why some people insist on
being on the bleeding edge (he says, as he writes this on his Mac Plus running
System 6.0.5).

Now, I'm seeing some real misinformation being posted here, now that the holy
Supra modem is shipping.  Howard Shubs firmly told the world that v.32bis was
simply v.32 (9600 bps modulation speed) with compressed data, and that v.42bis
was simply more compression, and therefore there's no use for computer to
modem speeds above 38,400 baud.  As many of us lurkers here know, that's
baloney.  v.32bis is a true modulation speed of 14,400 bps, and v.42bis adds
data compression to that, up to a theoretical 4:1 ratio.  The modem under
theoretical conditions can receive some information, expand it to 4 times its
transmitted size, and pass that amount of information to the computer.  And
what's 14,400 times 4?  57,600.  USR just came out with their new HST
modulation, with a true 16,800 bps modem to modem speed (proprietary, I know,
but it's there).  Hasn't Telebit had a 19,200 PEP for awhile?  Add data
compression to those figures and watch the necessary modem to computer link
jump above 38,400.

This is only one example of the wealth of misinformation being spread here on
the net, now that many people are for the first time getting their feet wet
with high speed modems.  When I first got mine I spent a lot of time lurking
here and in Fidonet, and kept my eyes open, and learned a lot in about three
weeks time.  There are knowledgeable people here, and simply listening to them
will do wonders.  Refraining from posting when you don't know what's up will
do much to increase the signal/noise ratio of this and other modem newsgroups. 
All this "Well, I heard it's like this..." is just so reminiscent of those
morons in college who spent their time not studying but rather gossiping with
other morons about what current rumor was about this professor's test, or that
professor's grading policies....

--Adam--
 
--  
Adam Frix via cmhGate - Net 226 fido<=>uucp gateway Col, OH
UUCP: ...!osu-cis!n8emr!cmhgate!20.18!Adam.Frix
INET: Adam.Frix@p18.f20.n226.z1.FIDONET.ORG