                   USING YOUR PC AS A TERMINAL
               by Curtis Chong and Steve Jacobson

     Note:  This report is provided to you courtesy of the National
     Federation of the Blind in Computer Science, Curtis Chong,
     President.  For further information, contact the National
     Federation of the Blind in Computer Science at 3530 Dupont
     Avenue North, Minneapolis, Minnesota  55412.  The phone number
     you can call during evening hours is (612) 521-3202.  You can
     also reach Curtis Chong and Steve Jacobson via NFB-NET ((410)
     752-5011).

A useful feature of IBM Personal Computers and compatible machines
is their ability to emulate a wide variety of terminals.  No, we
are not speaking about that part of the battery to which you attach
the wire.  Rather, when we use the term, "terminal," we are
referring to a device, used to communicate with a larger computer,
typically consisting of a video display and a keyboard.

There are a lot of different brands and types of medium to large
computer systems in use by businesses today, and each computer
system can communicate with different brands and types of terminals
and terminal protocols.  You hear about Wang terminals, IBM
terminals, DEC terminals, ASCII terminals, glass teletypes--the
list goes on and on.

Prior to the development of the PC and screen access hardware and
software for the blind, it was difficult if not impossible for
blind people to independently use many terminals.  There were
simply too many of them.  In 1977, the terminal that could not be
independently accessed was the IBM 3277.  Independent  access to
this device was achieved in the early 1980's, when IBM released its
talking 3278. However, all of that changed with the advent of the
PC.

As the PC began acquiring an increasingly large share of the
microcomputer market, commercial enterprises recognized a golden
opportunity to develop and market terminal emulation software and
hardware using the PC as the base platform.  Since potential
customers were already using the PC for other purposes, it was
reasoned that it would be more attractive for them to use the PC as
a terminal when required instead of purchasing a device that could
only perform a single function--that of a terminal.  The success of
PC-based terminal emulation systems today has proven the soundness
of this thinking.

The growing popularity of commercial terminal emulation systems was
paralleled by a growth in the use of speech and braille screen
access systems for the blind.  It just so happened that in many
situations, we could use our screen access technology to run the
PC-based, commercially-available terminal emulators, thereby
gaining access to more computers than just the PC itself.

The terminal emulation systems discussed in this report are grouped
into three distinct areas: emulation systems that communicate
through the PC's serial port, emulation systems that communicate
with the assistance of an adapter card that must be inserted into
one of the PC's expansion slots, and IBM 5250 emulation.


Terminal Emulation Through the Serial Port

Terminal emulation software that communicates through the PC's
serial port is most often used with a modem.  Using a modem, you
can contact remote systems using a standard telephone line.  Today,
modems can communicate at rates ranging anywhere from 300 bits per
second (baud) to an effective speed of 19,200 bits per second (with
proper data compression protocols in place).

Modems are not always used, however.  Oftentimes, it is possible
(and even desirable) to connect the PC's serial port directly to a
mid range or large computer.  This is done when the computer system
to be used is relatively close by--say within two-thousand feet.

Terminal emulators that communicate using the PC's serial port have
been the most compatible with screen access systems designed for
the blind.  Popular terminal emulation programs such as PROCOMM
Plus, QMODEM, and Telix work fairly well with screen access
hardware and software.  These commercially-available programs
enable the PC to emulate such popular terminals as the DEC VT-100,
the IBM 3101, IBM 3270 or 5250 terminals (with the proper protocol
conversion unit installed), and the ANSI.DBS terminal so popular
with today's electronic bulletin boards.  In addition to permitting
you to communicate interactively with remote systems, these
emulation programs support a variety of file transfer protocols
such as KERMIT, XMODEM, YMODEM, and ZMODEM.  Using these protocols
you can actually transfer files to a remote system (uploading) or
transfer files from the remote system to your PC (downloading). 
The only requirement is that the system with which you are
communicating support such file transfer operations.

When your PC is functioning as a terminal, it can communicate with
the remote computer in two different ways: line mode and full
screen mode.  The choice of which mode to use is, unfortunately,
not always yours to make.  It depends on the software on the remote
computer with which you are communicating.

Line Mode  When your PC communicates in line mode, you send the
computer at most a single line of data.  The computer may return a
single line of data or many lines of data, depending on the
response required.  Using this mode of interaction, you needn't be
bothered with the idea of a cursor per se (although one is
displayed on the screen to indicate where your next entered
character will appear).  You typically don't have to resort to any
sort of a "review mode" to have something repeated back to you; 
you simply enter a command, and the computer retransmits the
information to your screen.

Users of speech-based screen access systems typically prefer to
have everything spoken as it is written to the screen when
communicating with a remote system in line mode.  In most
situations, this practice works quite well, making it appear as if
the computer is automatically generating speech at just the right
time.

Full Screen Mode  In full screen mode, the computer expects to
communicate logically with you one screen at a time.  You typically
receive a formatted screen which you are expected to "update"
before sending it back to the computer.  You fill in the
appropriate areas of the screen with the information that the
computer requires, and the entire screen is sent back to the
computer only when all of the requested information has been
entered into it.  This type of interaction makes heavy use of a
cursor, and it is often necessary to resort to your screen access
system's "review mode" to examine relevant portions of the screen.

In thinking about full screen interaction, you might logically
conclude that data flows one screen at a time between the terminal
emulator and the remote computer.  Actually, the interaction takes
place at the character level.  As you move the cursor about the
screen or type information into a data field, that information is
sent to the remote computer and held in a buffer for later handling
by the application that processes the entire screen (e.g., your
editor, electronic mail package, compiler, or whatever).  Most
terminal emulators behave differently from other programs you run
on your PC in one important respect.  Instead of updating the
screen immediately after you press a key as your word processor or
data base program does, emulators typically transmit a character or
sequence of characters to the remote computer without updating the
screen.  Only when the remote computer returns a response (which
might be the single character typed or a sequence of codes to move
the cursor) does anything happen to the screen.

For example, if you press a right arrow key (to move the cursor one
position to the right), your emulator sends a code to the remote
computer which then returns a sequence of characters instructing
the emulator to move the cursor one position to the right.  It is
only then that the emulator will actually move the cursor.  This
creates an interesting side effect for a number of speech screen
access systems.  Ordinarily, when the left or right arrow key is
pressed, the screen access system announces the character upon
which the cursor lands after the move operation is complete.  The
screen access system is waiting for two things to happen before
speaking the character.  First, a small amount of time (perhaps 100
milliseconds) has to pass, and second, the screen has to settle
down (cease being updated).  For PC-based applications, this logic
works quite well.  However, when you are running a terminal
emulator, the above two conditions are satisfied before the remote
computer has a chance to send back the codes necessary to move the
cursor.  This results in the screen access system speaking the
character where the cursor was instead of the character that the
cursor eventually arrives at.

How to Know When you have Received the Last Bit of Data  If you are
interacting with a remote computer in full screen mode, and if you
choose not to have everything spoken as data is sent to the screen,
how then will you know when you have received the last bit of
information from the computer?  One way is to repeatedly strike the
cursor location key and "watch" the cursor move about the screen. 
Once the cursor stops moving, you can be fairly sure that the
screen has been fully updated.  Another approach is to use a
twedledump.

A twedledump is a small device that attaches to the end of a 25-pin
RS232 cable, such as that used to connect your computer's serial
port to an external modem.  Whenever data is transmitted over the
cable, the twedledump makes a continuous chirping sound.  When the
flow of data stops, the twedledump stops chirping.  A number of
blind computer users have found this to be a necessity when
connecting their computer to a remote system.  It enables them to
hear everything that happens on the line.  With a twedledump, you
can judge the data flow and determine if your screen is being
refreshed continuously or in jerks.  You can even tell if the line
is "dirty"--that is, causing garbage to be written to the screen.

A twedledump can be purchased for about $16 from Blazie Engineering
in Forest Hill, Maryland or from John Monarch in Frankfort,
Kentucky.  In its original form, the twedledump does not come with
all pins wired.  Ordinarily, this is not a problem.  However, if
you expect your modem to receive calls with a twedledump attached,
you should try to obtain a twedledump with all 25 pins wired.  We
have been able to obtain such fully-wired twedledumps from John
Monarch (525 Pawnee Trail, Frankfort, Kentucky  40601) for $25.


Terminal Emulation Using an Expansion Card

Using the appropriate software and circuit card, your PC can access
a whole new world of networks and computer systems.  These include
(but are by no means limited to) local area networks; Wang, IBM,
and other mid range computer systems; and mainframes supporting
3270 terminals.

Local Area Networks  Accessing a local area network with your PC is
not exactly like communicating with a computer using a terminal. 
It is more like adding programs and disk drives to your PC without
having to waste space on your hard disk.  Local area networks
enable you to transfer disk files from one PC to another and to
execute network versions of programs that corporations acquire for
less than it would cost to purchase individual copies of the
program for each PC work station.  Your screen access system will
probably be able to work well with the basic utilities of the
network (e.g., the LOGIN program, the interface program (for
communication between the computer and the communications card),
etc.), and there is a good chance that it will work with programs
that are accessible to your PC on the network.

Using Ethernet or token ring interface cards, it is possible for
your PC to access a local area network.  Blind PC users have been
successful in using Novell and IBM local area networks with a
variety of screen access systems.  This does not mean that they are
able to use all of the programs on the network, however--only that
they can get at the basic programs required to use the network. 
Just as some programs running on individual PC workstations do not
work well with speech, so it is with network versions of those same
programs.  So, while you will probably be able to use WordPerfect
in either a stand-alone or network environment, you will not be
able to use a graphics program in either.

Using your PC as a 3270 terminal  It is fortunate that in today's
world, there are a wide variety of 3270 terminal emulation systems
for the PC.  It is this type of terminal that provides the greatest
possible access to large IBM mainframe systems.

A 3270 emulation system for your PC typically consists of an
adapter card and some software.  Most often, the adapter card is
referred to as a 3278/79 adapter card.  In some instances, the
adapter card can be an interface to a local area network.  Typical
systems include IBM's 3270 Personal Communications program, IBM
Comm Manager (for OS/2 PM platforms), Attachmate's EXTRA! program,
and DCA's IRMA software.  These programs are often capable of
providing you with as many as four terminal sessions plus a DOS
window.  You can "toggle" between each session or window by
pressing a "hot key" sequence.  You can run your favorite word
processor in your DOS window, edit and compile your programs on TSO
with one 3270 session, and deal with your electronic mail on IBM's
OFFICE/VISION system in another.  Typical 3270 emulation systems
today also support file transfer operations between the PC and the
IBM mainframe (interfacing with IBM's IND$FILE program), and some
systems can even copy data from one 3270 session to another.

Typically, when using your PC as a 3270 terminal, there is no
automatic generation of speech.  In the 3270 environment, you can
move your cursor about the screen and hear individual characters,
words, or lines spoken.  You can even hear individual keystrokes
spoken as you enter them.  However, once you press Enter, you won't
be able to hear what is being sent to the screen.  Those of us who
are experienced 3270 terminal users have become quite adept at
watching the cursor until it settles down, then "reviewing" the
screen to determine what happened.  Others have been able to
develop automatic monitoring windows with their favorite screen
access systems so that, to a certain extent, automatic speech can
be generated as data is sent to the screen.

Systems that emulate the IBM 3270 terminal historically have not
been particularly friendly with screen access software for the
blind.  Thanks to advances in screen access technology and
adjustments made by developers of 3270 emulation systems, blind
people have access to more than one package.  However, there is
still no guarantee that your favorite screen access system will
work with every 3270 emulation system.  If you have a need to use
your PC as a 3270 terminal, you should still do some testing to
ensure that your 3270 emulation system of choice will work with
your screen access system of choice.  Don't be surprised if the two
are found to be incompatible.

Some screen access systems (e.g., JAWS, IBM Screen Reader for DOS,
FLIPPER, ASAP, and the Speaqualizer) have been found to work with
Attachmate's EXTRA!.  One of the authors of this report (Curtis
Chong) has been able to use DCA's IRMA software with the
Speaqualizer, and we are told that IRMA will work with some other
screen access systems such as GW Micro's Vocal-Eyes.  If you are
running OS/2 with IBM's Screen Reader/2, Comm Manager appears to be
your best bet, although some success has been achieved with Rumba
from Wall Data.  The end result of this discussion is to say that
If you have a need to use a 3270 terminal, you can be sure that
there is a way to get your PC to emulate that particular type of
device.  However, don't be surprised if the emulation system
preferred by your employer does not work with your screen access
system.  Either you will have to get a new screen access system, or
your employer will have to allow you to use a 3270 emulation system
that is more compatible with the screen access system on your PC.


IBM 5250 Terminal Emulation

We have decided to devote an entirely separate section of this
report to a discussion of how your PC can be configured to emulate
an IBM 5250 terminal.  There seems to be a lot less information
available about this particular type of emulation.  Yet,
independent access to IBM mid range computers seems to us to be no
less important than access to IBM mainframes.

Just as the IBM 3270 series of terminals is a de facto standard for
large IBM "mainframe" computers, the 5250 series is a standard for
IBM's smaller "mid range" systems.  These include the System 36 and
the AS-400.  When you attempt to make your computer emulate a 5250
terminal using speech, braille, or large print, you will find the
same difficulties confronting you that exist in the world of 3270
terminals.  On the bright side, though, since 5250 terminals are
common in the work place, there is a variety of approaches that can
be used to enable your PC to emulate one, and it is likely that
more than one approach will work in a given installation.

Probably the simplest (and also the most expensive) way to get your
computer emulating a 5250 terminal is by using an external
"protocol converter."  This device is simply a box that connects
your PC to the computer system that expects to "talk to" a 5250
terminal.

A protocol converter is an interesting machine.  In addition to
transforming one connector type into another (e.g., RS232C
connection to a coaxial cable connection), it also converts one
communication protocol into another.  Protocol conversion simply
means that the box takes the commands that were intended for one
type of terminal and changes them into commands that can be
processed by a different type of terminal.  So how does this help
you?

As we said earlier, programs such as TELIX, QMODEM, PROCOMM, and
many others can emulate terminals such as DEC's VT-100.  As it
turns out, terminals like the VT-100 are supported by many protocol
converters.  Therefore, if you install the appropriate protocol
converter, you can then use a telecommunications program to access
the IBM computer by simply emulating a terminal that the protocol
converter supports.  Your telecommunications software thinks it is
communicating as a VT-100, for example, and the mainframe thinks it
is talking to a 5250 terminal.  Only the Protocol Converter knows
the truth of the matter, except when things don't quite work right,
of course.  This is a viable approach, particularly if your
coworkers are accessing a mid range system using 5250 terminals
without the benefit of their own personal computer workstation.

Although this seems simple on the surface, there are certain
drawbacks to the protocol converter approach.  First, protocol
converters are more expensive than terminal emulation cards that
are installed inside a PC.  Prices in excess of $1,200 are common,
and this likely won't include the cost of the telecommunications
software that you must run on your PC.  Secondly, protocol
converters are not as easily modified by the manufacturer when new
5250 features become available.  For this reason, they sometimes
lag behind the "leading edge of technology."  For example, it is
common for a 5250 terminal to have the ability to maintain multiple
sessions simultaneously, but not all converters support this
feature.  Third, using a protocol converter, the ability to
transfer files from your PC to the host computer (and vice versa)
may be diminished or non-existent.  Although this may not be
important if your coworkers can't do this either, it may become a
stumbling block if you wish to make grade II braille copies of
documents that reside on the host computer.  Finally, you will
likely be the only person using a protocol converter in your place
of employment.  Your coworkers will either be using 5250 terminals,
or they will be using PC's as workstations to access the central
computer.  This means that you will be on your own.  On the plus
side, however, there are instances where a company may use a
protocol converter to support several PC's or a network.  With any
luck, you may well fit into this configuration with little or no
difficulty.

Another means of emulating a 5250 terminal with your PC is by using
a terminal emulation card.  These are circuit boards that occupy a
slot inside your PC.  Such cards generally come with software that
must be run on your computer.  Although most emulation cards can be
made to operate with one screen access package or another, few
emulation systems, if any, will run with all screen access
software.  Before you go back to reread that last sentence, it
simply means "Be careful."

The major problem with 5250 emulation cards and their software is
the way in which some of them "take over" the keyboard.  IBM's
PC-Support terminal emulation software is a case in point. 
Although it works with the IBM Screen Reader, it does not coexist
well with other screen access software.

In the past, the "keyboard takeover" problem caused the termination
of all speech as soon as the PC was placed in terminal mode. 
Things are a little different now, though.  Most speech screen
reading software today can be made to watch specific areas of the
screen and inform the user of changes.  As a rule, this activity
will continue even if the keyboard has been expropriated by the
terminal emulation software.  Several screen access products have
gone to great lengths to "steal" the keyboard back again, and there
are screen access products that do not depend on the keyboard at
all, having their own dedicated separate keypad.  Therefore, it is
impossible to categorically say that a given 5250 emulation system
won't work with screen access technology.  If you have coworkers
accessing a mid range system using PC's and terminal emulation
cards, try your speech software and hardware on their machines.  If
you use speech, check to see if your keystrokes are spoken
properly, and test the cursor movement keys to determine whether
they act as they should.  Keep in mind that some keys traditionally
thought of as cursor movement keys may have no function when
emulating a 5250 terminal, but the LEFT, RIGHT, UP, and DOWN ARROW
keys should behave as you would expect.  You might be pleasantly
surprised to find that everything works just right.  if not, read
on.

Believe it or not, from time to time, particular 5250 emulation
systems come to our attention that are found to work with most if
not all screen access products.  Unfortunately, this "feature," as
those of us who are blind see it, often gets inadvertently dropped
when a new version of the emulation system comes out.  On the
bright side, manufacturers are becoming more and more responsive
when contacted by blind consumers and screen access software
providers.  In general, such "friendly" emulation cards can simply
be installed and run.  In some instances, it may be necessary to
load the terminal emulation software prior to activating the screen
access software.  There are usually provisions to automate this
process through an appropriately configured PC BAT file.

In some installations, 5250 terminal emulation is integrated into
a local area network (LAN).  If the 5250 emulation software is
loaded from disk on your individual PC, it can probably be replaced
with another package if it is found to be incompatible with your
screen access system.  However, if the emulation software is loaded
from another PC on the LAN, you may have no choice other than to go
screen access shopping.

Now, let's get down to specifics.  If you have tried to get speech
to work on a coworker's machine and met that all too real stone
wall head-on, what can you do?  First, contact the company from
which you purchased your screen access software.  After explaining
what you are trying to do, ask them if there are settings that you
can try in an effort to resolve the problem.  Since the screen
access marketplace is constantly changing, you might also ask if
there are any new versions of the screen access software pending
that will deal with the stolen keyboard scenario.  If the answer to
both questions is "no," and if you would rather not change screen
access software, you must investigate one of the more "friendly"
emulation systems discussed at the end of this report.

If you are not committed to your present screen access software, or
if you are just starting out, arrange to try some other screen
access systems to see if they work.  If you already own Artic
Business Vision, ask to try "The Gizmo," which is a separate keypad
that may allow you to use Artic Vision with most 5250 emulators. 
Also, the Speaqualizer and the IBM Screen Reader both have external
keypads that significantly reduce their dependence upon the PC's
keyboard.  These two systems have both been reported to work where
others have not.  Flipper and ASAP both manage to "steal back" the
keyboard in some instances, thereby allowing them to function even
though they do not have separate keypads.  Both Vocal-Eyes and JAWS
have been reported to function well with alternative 5250 emulation
systems.  It is likely that other screen access software will find
solutions to this problem as well.  So, be sure to check with your
preferred vendor, regardless of whether or not that vendor is
mentioned here.

If you need to investigate alternative 5250 emulation cards or
protocol converters, check out the list at the end of this report. 
Remember, if you ask most manufacturers if their cards work with
screen access technology, they will probably not know.  Chances are
that they have never heard of a screen access system.  Dealers will
also not understand why you want to use a protocol converter to
change 5250 terminal commands to that of another when using a PC. 
They are used to thinking of these converters as a means of
connecting non-IBM terminals.  Your best bet is to contact other
blind consumers or dealers who have made it their business to find
out.  Good luck!Terminal Emulators Using the Serial Port

Telix
Exis, Inc.
P.O. Box 130
West Hill, Ontario Canada M1E 4R4
Phone: (416) 289-4641

Qmodem
Mustang Software, Inc.
P.O. Box 2264
Bakersfield, CA  93303
Phone: (800) 999-9619

PROCOMM Plus
DATASTORM TECHNOLOGIES, INC.
P.O. Box 1471
Columbia, MO  65205
Phone: (314) 443-3282 (business office)3270 Terminal Emulation Systems

EXTRA!
Attachmate Corporation
13231 Southeast 36th Street
Bellevue, Washington  98006
Phone: (206) 644-4010

IRMA
Digital Communications Associates (DCA)
1000 Alderman Drive
Alpharetta, Georgia  30202-4199
Phone: (404) 442-4000

Rumba
Wall Data
11332 Northeast 122nd Way
Kirkland, WA  98034
Phone: (800) 487-86225250 Terminal Emulation Systems

Andrew Corporation (formerly KMW Associates), Austin, Texas, (800)
     531-5167:  This company carries external 5250 protocol
     converters that should work with telecommunications programs. 
     Approximate Price: $1,300.  They also sell internal cards, but
     these have not been tested for screen access compatibility.

Black Box Corporation, Lawrence, Pennsylvania, (412) 745-5565: 
     This company produces both Protocol Converters and internal
     5250 emulation cards.  Although not tested, they do produce
     converters that emulate other terminal types.  Price range:
     $1,200-1,500.  Their internal cards have not been tested for
     compatibility with screen access software.

Computer Labs Inc. (CLI), Anaheim, California, (714) 779-2662 (See
     Also Second Sight):  Certain versions of their 5250 emulation
     cards and software work with Vocal-Eyes and some others. 
     Price Range:  $500-800.  To get up-to-date information as to
     which versions work well and to order, contact Second Sight
     listed later.

Henter-Joyce Inc, St. Petersburg, Florida, (813) 576-5658:  They
     sell a 5250 emulator card manufactured by MUCS Labs that works
     with JAWS and probably with other screen access software. 
     Approximate Price: $800.

MUCS LABS (800) 361-1965:  See Henter-Joyce Inc.  They manufacture
     an internal 5250 card that is reported to work well with some
     screen access software when other cards do not.

Second Sight, Littleton, Colorado, (303) 795-4655:  As a Vocal-Eyes
     dealer, this company is aware of cards that work with that
     program.  In particular, they sell the appropriate versions of
     the CLI card mentioned above which may work with other screen
     access software as well.
