HSTnet HST Echo HSTnet 1/0 (813) 394-6488                          May 1994
FAQ - Fequently Asked Questions

Q.   What is HST

A.   HST is a registered trademark of the U.S. Robotics Company (USR).  It
was originally used to indicate "High Speed Technology."  Before USR
trademarked HST, it was also used by Microcom to describe modem technology.

HST is also the name of an HSTnet echo that supports users of US Robotics
and other modems based on that technology.  Data Race, Concord, Miracom
and others used or use HST technology.

The Courier HST was the first high speed modem released by US Robotics.
It's primary transmission speed was 9600bps.  The use of HST error
correction increased the maximum transmission speed possible to 11910bps.
Actual maximum speeds were in the vicinity of 11700bps.  Gradually the
modems increased in speed from 9600 to 14400.  The latest version is now
16800 and can be had with facsimile Class 1 and Class 2.0.  HST is a unique
assymmetrical channel configuration.  MOST of the usable bandwidth is
concentrated in sending data one way at time.  Since the vast majority
of data transmission is highly asymmetrical in nature, this has proven a
very efficient transmission method.  Speeds on HST may be expressed with
a divider indicating speeds on both channels.  The original HST transmitted
at 9600/300.  Later versions went to 14400/300, 14400/450, and 16800/450.

Q.    What is a Courier modem?

A.    US Robotics is the manufacturer of several different model ranges of
modems.  They offer modems for the averager user in the Sportster line.  The
Courier line adds features for heavy duty use, such as the ASL features.
The World Port line of portable and PCMCIA modems are intended for
users of portable computers.  While the Shared, Network, and Rack Mount
modem lines are more likely to be found in Network environments.

Any of these modems will perform it's intended functions.  The Courier will
usually perform a bit better than the Sportster due to the added features of
ASL, and other performance enhancements.

Q.    Dual Standard, what does that mean?

A.    The original US Robotics High Speed modem was the Courier HST (9600).
Later the CCITT (now the ITU) set down specifications for a new 9600 protocol.
That protocol was V.32(9600).  By that time the HST was operating at 14400 bps
and there were tens of thousands of HST modems in use.  The best support
both the new V.32 protocol modems and the orignal HST modems, a new Courier
called the Dual Standard was created which contained BOTH protocols.

The newest Dual Standard, now support the latest versions of HST (16800), V.32
V.32bis(14400), Terbo (21600), and V.FC (28800).  The newest V.FC Dual
Standard will also be upgradable to the new ITU 28800 bps protocol known as
V.34 using user downloadable software run from the MS/Dos command line.

Q.    What is HST Cellular?

A.    HST Cellular is US Robotics new protocol for cellular data transmission.
it is based on the HST16800 protocol. Extensive testing shows that data
can be transmitted from a moving car at 8,000bps and from a stationary car
at speeds to 11,000 bps.  This is a significant improvement over other
cellular protocols such as MNP10.

Q.    What is V.32?

A.    V.32 is a protocol type acceptance designation from the ITU (formerly
CCITT).  This is an international specification intended to maximize
compatibility between different makes of modems.  There are many ITU
modem protocols.  The V.32 protocol means that there will be two channels
that send and receive data at a maximum rate of 9600bps.  Both channels
under V.32 operate at the same speed.  The use of the available acoustic
bandwidth is equal for each channel and overlapping.  The use of a very
sophisticated echo cancellation algorithm and additional processing power
allows a V.32 modem to send and receive up to 9600 bps data simultaneously.
V.32 modems generally support error correction, and compression.

Another version of V.32 is called V.32bis.  This is a faster improved
version that can transmit at 14400 bps on both channels.  V.32 and V.32bis
modems from US Robotics also have the feature of ASL.  Adaptive Speed
Leveling allows either channel to be adjusted in speed independantly to
maximize throughput.  Connect speeds of 14400/9600 or other combinations
of valid fallback speeds are common.

Q.   What is V.32TERBO?

A.   Terbo is a high speed protocol developed by AT&T capable of 19200 bps.
While V.32 normally operates at 9600 bps and V.32bis operates at 14400 bps,
Terbo is designed to operate at 19200 bps.  An added feature of USR Courier
modems is that ASL allows two Courier modems to operate at 21600 bps.

An error correction protocol known as Trellis Encoding allows HST and
V.32 to operate on phone lines with higher levels of noise than modem
protocols that do not use TCM.  The examination of the bit pattern used
in TCM produces a picture refered to as a Constellation Pattern.

The V.32 Constellation Pattern did not use all of the bit positions available
for the transmission of data.  Those not used were usually not available un-
less the telephone lines were of exceptionally good transmission quality.
The Terbo protocol uses up more of the remaining bits in the pattern, and as
a result is not as insensitive to line noise and impairments as V.32 or
V.32bis modems, although very similar otherwise.


Q.    What is ASL

A.    ASL is an acronym meaning Adaptive Speed Leveling.  While this term
sounds as if it relates ONLY to the initial speed negotiation at link up, at
various times USR personnel have discussed OTHER ASL functions as well.

One function of ASL is rapid link negotiation.  USR V.32 modems may link as
quickly as 4.5 seconds, while other typical modems link as slowly as 8-45
seconds.  Another function is negotiation of the best speed per channel.
When you see 16800/14400 this is an indication that ASL has determined there
is a problem with one of the channels.  Without ASL such a connection would
be at 14400/14400, limited by the slowest supported speed.

ASL also is responsible for rapid retraining.  When the modem senses that
line conditions improve the modem is capable of shifting to a faster speed.
The retraining is done at a higher speed than many modems, and that is also
part of ASL.  During the initial negotiation of speeds, all high speed modems
connect at 2400 bps initially.  Negotiating, the modems decide on which common
features are supported and the most efficient are chosen.  This involves ASL
when a Terbo connection senses another Courier Terbo and allows shifting as
high as 21600 bps.

Q.    What is MNP

A.    The Microcom Network Protocol is a number of protocols that provide
error correction and increasingly efficient data compression.  MNP is described
in levels starting with level 1.  Levels 1-4 are considered public domain
and are found in nearly every modem made.  The compression and error correct-
tion provided by levels 1-4 result in a bit rate transmission increase of
approximately 20% minus error correcting bits.  Level 10 is a special version
designed to aid in cellular telephone data transmission.  All MNP levels
above 4 carry licensing fees to the modem makers.  Level 5 is a commonly
found compression algorithm found in most modems sold today.


Q.    What is V.42, V.42bis, Lap-m

A.    V.42 is a negotiation protocol for error correcting modems.  During the
connection process, the modems tell each other which common and desireable
features are supported by both modems.  The modems will select by default the
most efficient error correcting and compression techniques.  A more efficient
compression technique than MNP5 is called V.42bis.  A more efficient error
correction technique than MNP1-4 is called Lap-m.  When V.42 is executed at
the connection phase, it looks for the highest level efficiency both modems
can support.  The prefered defaults are Lap-m and V.42bis.


Q.    What is a Bler?

A.    Bler means Block Error.  This is a function of error correction.  With
an error correcting modem, any data that fails it's verification check is
resent.

Q.    What is ARQ?

A.    Automatic Resend Request.  This is the US Robotics way of labeling the
various error checking protocols.  The original HST modem used a proprietary
technique that was similar to MNP and the resulting connect string sent was
9600/ARQ.  All USR modems send connect message of ARQ to indicate an error
correcting protocol is detected and in use on both modems.

Q.   Can I upgrade my old HST modem (9600, 14400 or 16800 bps)

A.   Maybe.  Several upgrades may be in effect from time to time.  One
such upgrade for the very old HST14400 modems is to Dual Standard (14400HST/
V.32 9600) for $199.  At various times other upgrades or trade in programs are
in
effect. Most upgrades now are trade in programs that are in effect for a
short period of time when NEW modems are introduced.  The ONLY way to know
if a modem is upgradable is to call USR.

ALL USR V.Small chassis Couriers are upgradable via daughterboard changes.

The Tech Support number is (708) 982-5151.

Q.   How do I contact USR directly?

A.   You can use a modem to call their BBS at 708-982-5092.  The BBS runs a
Total Control rack mount with 8 Courier Dual Standard modems on it.
There is a section where you can download information on the Sysops program,
products, pictures of modems, and technical tips.   There is also a section
that contains a local USR message area for questions to USR.

You can also call USR at 800-342-5877 and talk to sales.  Or you can call
Technical support at 708-982-5151.

USR also has an automated Facsimile Service at (708) 762-6163.
Compuserve:  GO USROBOTICS
INTERNET:  support@usr.com

About US Robotics Company, Skokie, Illinois

Phone numbers:
                 800-342-5877  Fax 708-982-5235
Canada           800-553-3560
Tech Support     708-982-5151
Tech Support RMA 708-892-0823
BBS              708-982-5092 (8 lines Terbo)
FAX on Demand    708-762-6163


Q.    How do I order a modem on the USR sysops program?

A.    Call the USR company BBS.  The number is 708-982-5092.  This is the ONLY
way to order a modem on the Sysops program.

Q.    What do I have to do to qualify for the Sysops program?

A.    First you have to be operating a BBS for at least six months.  You
should obtain the latest copy of the Sysops Program offer form USR's BBS.
Then you must be willing to accept the conditions of the Sysop's deal in order
to be considered to receive a modem at the special Sysops pricing.

             ***** From Sysdeal.TXT of 4/25/94*****
If you are a registered owner of any of the following software packages
US Robotics automatically waives the 6 month verification portion of the
qualifications.  US Robotics is proud to have entered into this agreement
with:

**********************************************************************

The participating vendors are:

PC Board(Clark Development )            (800)356-1686 Voice Dos
                                        (801)261-8976 BBS

Wildcat!(Mustang Software Inc.)         (800)999-9619 Voice Dos
                                        (805)873-2400 BBS

Power Board(NUIQ Software Inc.)         (914)833-3479 Voice Dos
                                        (914)833-1479 BBS
                                        (914)834-7830 BBS
                                        (914)833-3623 FAX

Searchlight                             (800)780-LITE Voice Dos
                                        (516)689-2566 BBS

Roboboard                               (819)682-6670 Voice Dos
                                        (819)682-7771 BBS

T.P Board and Front Door                (201)941-1110 Voice Dos

Remote Access(Wantree Development)      (800)648-9800 Voice Dos
                                        (913)441-0595 BBS

The Major BBS (Galaticomm, Inc.)        (800)328-1128 Voice Dos
                                        (305)583-7808 BBS

First Class (SoftArc)                   (416)299-4723 Voice Mac(E-Mail)
                                        (416)609-2250 BBS

TeleFinder (Spider Island)              (714)669-9260 Voice Mac
                                        (714)730-5785 BBS

AmiExpress   Phone to be announced.... Amiga

DLG  (TelePro Technologies)             (403)341-7826 Voice Amiga
                                        (403)347-3269 BBS

Celerity/Alacrity (Lexicon Computing)   (310)693-9405 BBS   Dos

TEAMate (MMB Development Corp)          (310)318-1322 Voice Unix
***********************************************************************
=============================================================================

For details see the Sysdeal.TXT file on USR BBS 708-982-5092

Q.   Are there requirements to advertise the modem that I buy as a Sysop?

A.   Yes, you are required to operate the BBS and to carry a notice to all
callers that you are using a USR modem, and hopefully which model etc.  The
time period of this requirement has typically been six months.  See the current
sysdeal.txt file on USR's BBS for precise details.

Q.   Why are they so strict?

A.   Because many non-sysops have attempted to obtain the special pricing
which they do not deserve.

Q.   Why does it take so long to get a USR when I can order other modems and
get them almost immediately.

A.   Frequently USR announces new modems when the production lines are not
operating.  New modems will have long delays before the first orders are
filled.  USR also makes a limited amount of modems available to Sysops, and
these amounts can run out.  There is no retail sales department at USR.
They ship on a regular schedule.  Other companies sell retail from the factory.
Recent shipments from USR to sysops have been accomplished in as little as 7
days during regular production.  A year old backlog was worked off some time
ago and has not recurred.

Q.   If I can buy a modem direct from other modem makers, why does USR have
such a strict policy?

A.   One reason is to protect the distributors and dealers who sell USR
modems.  Some companies will sell modems in competition to their dealers and
distributors.  Such companies dealers are not likely to view the sysop as a
customer but as a competitor who has taken away profit.  Sysops using USR
modems who advertise those modems on their BBS's provide a service that is
likely to benefit USR modem dealers.  And such sysops are much more likely to
recieve support from dealers for the advertising the Sysops perform.

Q.   Does USR accept Credit Cards in payment?

A.   Yes, USR does now accept credit cards.

