tsai@milton.u.washington.edu (Men-Shen Tsai) (11/25/90)
I am concerning buying a new modem to replace my old one. I reviewed the
Computer Shopper and found out there are different kinds of 9600 bps
modems. Several terms I don't really understand. Can some one in the
net help me to figure out the meaning of these terms?
1. What does HST mean, and what are the differences between HST and
V4.2?
2. Some modems are able to transmite in the speed of 19.2K if it is
in COMPRESS mode. What does the COMPRESS mode do when I transfer
files?
3. Is there any standard amoung these high speed modems? Is there any
compatiable problems between modems?
4. US Robotics modem has two different models, HST 9600 and Dual standard
9600. The price difference between these two models is about $300.0.
What does DUAL STANDARD mean here?
Thanks in advance.
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Mail: tsai@milton.u.washington.edu
University of Washington, Seattle, WA
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6600prao@ucsbuxa.ucsb.edu (Parik Rao) (11/25/90)
HST = high speed technology. Another "stupid buzzword". Compress mode basically squashes the data down, its ineffective unless you are transferring large amounts of ascii data (in fact, it tends to slow down zip files!). Unfortunately, most 9600 baud modems don't talk to other 9600 baud modems. Bummer. I haven't kept up with it too much, but I'm sure USR still thinks they've got the coolest modem, Hayes thinks they've got the coolest, and everyone else is still trying to break into the market. Dual standard HST's have the prop HST 9600 communication, and either v.32 or v.42bis built in. I'm not sure, but I believe this means the DS can talk to either a HST or a Hayes 9600. I've owned a usr HST for 2 years (its one of the first ones... peaks out at 1100cps!) and am very satisfied. My expierences have been that almost every BBS under the sun uses the usr HST. By buying a usr HST 14.4k (around $550) you should have a happy modemlife. I bought mine under the sysop deal for a real nice price [back then], USR really established the sucker by having it nicely priced for sysops. Check out the BBS's you'd use it on, and whether your university has a 9600 baud dial-in (and if so, what type of modem they are using). Then pick up one. I wouldn't bother with a dual standard, its too expensive and I still can't figure out why anyone (besides sysops, perhaps) would want the "alternative" 9600 connection.
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (11/26/90)
In article <11623@milton.u.washington.edu> tsai@milton.u.washington.edu (Men-Shen Tsai) writes: | 3. Is there any standard amoung these high speed modems? Is there any | compatiable problems between modems? Three standards of interest: V.32 for 9600 baud connection, V.42 for error correction, and V.42bis for compression. Proprietary protocols are PEP and HST, among others. Even with the standard you may have problems, but V.32 is slowly coming into common use. I don't think it's the best technology, but if you want a fighting chance to talk to other modems, that's the one to get. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me
silver@xrtll.uucp (Hi Ho Silver) (11/26/90)
In article <11623@milton.u.washington.edu> tsai@milton.u.washington.edu (Men-Shen Tsai) writes:
$I am concerning buying a new modem to replace my old one. I reviewed the
$Computer Shopper and found out there are different kinds of 9600 bps
$modems. Several terms I don't really understand. Can some one in the
$net help me to figure out the meaning of these terms?
If there's a FAQ here, these should be in it (and if they are, they should
be read ...)
$1. What does HST mean, and what are the differences between HST and
$ V4.2?
HST (High Speed Transfer ... or is it Transmission?) is USRobotics'
proprietary modulation scheme to achieve higher-than-2400 bps throughput.
It goes up to 14.4 kbps, and was devised back in the days when there wasn't
even a 9600 bps international standard. If you buy the USR HST modem,
you'll be able to communicate at 14.4 kpbs with another USR HST modem, but
only at 2400 bps with other manufacturers' modems. Also, this is an
asymmetrical protocol - while there is a channel in one direction running
at 14.4 kbps, the return channel runs only at 450 bps. For many users,
this is not a problem (downloads from a BBS or remote control of a PC,
for example, are largely one-way transfers). However, if you're using
it to do UUCP between Unix boxes, you'll get terrible throughput since
the 450 bps channel won't satisfy the protocol.
As for V4.2, there's no such thing. Perhaps you mean V.32, which is the
CCITT international standard (heh) for 9600 bps modems. Perhaps you mean
V.42, which is the CCITT international standard for error correction (this
standard includes LAP-M and MNP level 4).
BTW, the reason I said (heh) beside V.32 is that if you happen to buy
V.32 modems from different suppliers, they may or may not work with each
other. For more info on this, read the latest PC Magazine.
$2. Some modems are able to transmite in the speed of 19.2K if it is
$ in COMPRESS mode. What does the COMPRESS mode do when I transfer
$ files?
Well, as one would probably expect, it compresses them. Or, to be
more precise, it attempts to compress them. MNP level 5, for example,
will compress text quite well, executables fairly poorly, and may actually
provide worse throughput when transferring pre-compressed files such as
.ZIP archives. V.42bis, which is CCITT's standard for data compression,
provides significantly greater compression on most files than does MNP 5,
and it will simply allow pre-compressed files to flow through unhindered.
With MNP 5, you can sometimes double your throughput, although you'll
rarely get this much. V.42bis works better; it's supposed to theoretically
compress by up to a factor of four, though 2-3 would be more realistic
for most applications.
$3. Is there any standard amoung these high speed modems? Is there any
$ compatiable problems between modems?
Yes, and yes. See above.
$4. US Robotics modem has two different models, HST 9600 and Dual standard
$ 9600. The price difference between these two models is about $300.0.
$ What does DUAL STANDARD mean here?
Actually, USR has three modems. They have a V.32 modem which uses the
standard V.32 modulation techniques to achieve 9600 bps communications.
They have an HST modem which uses their proprietary HST modulation to
achieve 14.4kbps communications. They also have a Dual Standard modem which
will use either.
You are apparently considering USR (really? :-) Many BBSs use HST
modems, so you will be able to enjoy very high throughput with such BBSs
(check with the sysops before purchasing, if at all possible, to find out
if your favourite BBSs are HST-equipped). Keep in mind, though, that
the HST-only modem will connect with non-HST modems at a maximum speed of
2400 bps. That's the reason why USR sells a Dual Standard modem - it will
allow 9600 bps connections with V.32 modems (assuming, of course, that the
two modems happen to get along ...) As far as quality goes, USR has an
excellent reputation.
Two other things to keep in mind if buying USR (or, for that matter,
with many other manufacturers) have to do with the various CCITT standards.
Many manufacturers have recently added V.42bis data compression (and, a
few months ago, V.42 error correction) to their modems. Make sure you
get the most recent model, or else you might not be getting these protocols.
Also, the V.32bis standard for 14.4kbps communications will be out next
year; at that time, you can once again expect many manufacturers to
scramble and introduce V.32bis modems. Should you wait? It depends on
your present communications needs and equipment, and your future
communications needs. Keep that in mind when buying.
--
__ __ _ | ...!nexus.yorku.edu!xrtll!silver | always
(__ | | | | |_ |_) |----------------------------------| searching
__) | |_ \/ |__ | \ | if you don't like my posts, type | for
______________________| find / -print|xargs cat|compress | SNTFtom@bears.ucsb.edu (Tom Weinstein) (11/28/90)
Well, since I looked at the new USR modems at Comdex, I guess I should say something about this. In article <1990Nov26.031104.8597@xrtll.uucp>, silver@xrtll.uucp (Hi Ho Silver) writes: > HST (High Speed Transfer ... or is it Transmission?) is USRobotics' > proprietary modulation scheme to achieve higher-than-2400 bps throughput. > It goes up to 14.4 kbps, and was devised back in the days when there wasn't > even a 9600 bps international standard. If you buy the USR HST modem, > you'll be able to communicate at 14.4 kpbs with another USR HST modem, but > only at 2400 bps with other manufacturers' modems. Also, this is an > asymmetrical protocol - while there is a channel in one direction running > at 14.4 kbps, the return channel runs only at 450 bps. For many users, > this is not a problem (downloads from a BBS or remote control of a PC, > for example, are largely one-way transfers). However, if you're using > it to do UUCP between Unix boxes, you'll get terrible throughput since > the 450 bps channel won't satisfy the protocol. [ ... ] > Actually, USR has three modems. They have a V.32 modem which uses the > standard V.32 modulation techniques to achieve 9600 bps communications. > They have an HST modem which uses their proprietary HST modulation to > achieve 14.4kbps communications. They also have a Dual Standard modem which > will use either. The USR Courier HST Dual Standard modem has two high speed modes. One is symmetric and goes at 14.4 kbps BOTH ways. The other is asymmetric and goes at 38.4 kbps one way and 450 bps the other. Another nice thing about it is that is monitors the line quality and slows down if the quality gets poor. Lots of modems do that, but the USR speeds up again if the quality gets better which I don't believe anyone else does. The Dual Standard also supports V.32bis and V.42bis. USR also has two other modems that are each one half of the Dual Standard. One supports the HST standard and the other does V.32bis and V.42bis. -- He is Bob...eager for fun. | Tom Weinstein tom@bears.ucsb.edu He wears a smile... Everybody run! | tweinst@polyslo.calpoly.edu
fenger@buster.uucp (Steven V Fenger) (12/03/90)
In article <7435@hub.ucsb.edu> tom@bears.ucsb.edu writes: >Well, since I looked at the new USR modems at Comdex, I guess I should >say something about this. > >The USR Courier HST Dual Standard modem has two high speed modes. One >is symmetric and goes at 14.4 kbps BOTH ways. The other is asymmetric >and goes at 38.4 kbps one way and 450 bps the other. Another nice thing >about it is that is monitors the line quality and slows down if the >quality gets poor. Lots of modems do that, but the USR speeds up again >if the quality gets better which I don't believe anyone else does. > >The Dual Standard also supports V.32bis and V.42bis. > >-- >He is Bob...eager for fun. | Tom Weinstein tom@bears.ucsb.edu >He wears a smile... Everybody run! | tweinst@polyslo.calpoly.edu Last time I heard, V.32bis is no where close to being approved. Hayes, US Robitics and some European companies were still battling it out over what the standard should be. V.32bis is still a year away. Steven Fenger fenger@buster.cps.msu.edu