MOVING PROGRAMS BETWEEN YOUR IBM-PC AND BRAILLE 'N SPEAK

               by Jerry Weichbrodt

If you have an MS-DOS computer with a serial port, a communications 
program, and a 3-1/2-inch disk drive, you can not only load text files 
into the Braille 'n Speak, but you can also load external programs from 
disk.  Standard Braille 'n Speak disks are MS-DOS compatible, so they may 
be read on any IBM-PC-COMPATIBLE computer with the correct type of floppy 
drive.  Many other articles have been written about transferring text and 
braille files between IBM computers and the Braille 'n Speak, so I will 
confine my discussion to the subject of loading programs.  This ability 
to load a program through one's IBM computer is not a well-documented 
capability, so I hope to make it a better-known option.

The first important point to remember about Braille 'n Speak programs is 
that they consist of binary data which must be transferred to the Braille 
'n Speak without any errors or garbling.  An error-correcting protocol such 
as Ymodem should be used to load a program so that no errors creep in.  The 
second important point is that program files contain 8-bit data.  This 
means that both the IBM computer and Braille 'n Speak must be set for 8 
data bits.  As usual, the baud rate and number of stop bits must agree as 
well.  Parity should be set to "none."

Once the Braille 'n Speak and computer are connected together correctly 
and the Braille 'n Speak's serial port parameters are set as you want them, 
you should enable the serial port on the Braille 'n Speak.  I suggest 
opening a garbage file on the Braille 'n Speak so that any garbage 
characters that come from the IBM computer don't go into a file you care 
about.  At this point you should start your communications program and, if 
necessary, configure its communications settings.

If all is well, your IBM computer and Braille 'n Speak should be 
communicating together properly.  You should be able to send data in both 
directions between computers.  You might want to try typing data on your 
Braille 'n Speak to see that it makes it to the PC and vice versa.

Now that your computers are talking to each other, you can begin loading 
whatever files you like from your Braille 'n Speak disk to your Braille 'n 
Speak.  To do this, get your Braille 'n Speak ready to receive a file 
by issuing the O chord, F command to get to the file menu.  Issue the T 
chord command to get to the file transfer menu.  Choose R to receive a 
file.  Choose the protocol you plan to use for the transfer.  If you choose 
Xmodem protocol, you will also have to tell the Braille 'n Speak what 
to call the file it's about to receive.  At this point, your Braille 'n 
Speak should tell you to start the transfer from the PC end.  You should 
now issue whatever command is necessary to start transferring the file from 
the PC end using the same file transfer protocol you specified on the 
Braille 'n Speak end.

From here on in the file transer should proceed without you having to do 
anything.  When the file finishes being transferred, your Braille 'n Speak 
should say "OK."

Here are a few considerations to keep in mind when choosing the protocol 
to use in a file transfer.  Xmodem is available in virtually every 
communications program for the PC, but it has some serious disadvantages.  
In comparison to newer protocols that send data in larger blocks, Xmodem is 
quite slow in transferring files.  A lot of time is wasted in sending short 
data blocks and waiting for both sides of the transfer to decide whether 
the block arrived at its destination successfuly.  This disadvantage can be 
greatly reduced by using Xmodem-1K instead of standard Xmodem.  The block 
size in Xmodem-1K is 1024 rather than 128.  Another disadvantage of Xmodem 
is that it requires you to give the name of the file to be transferred 
to both the sending and receiving computers.  A final disadvantage of 
Xmodem is that it often causes extra characters to be added to the end 
of the file being transferred.  Xmodem doesn't understand blocks of data 
that are any smaller than 128 bytes.  In the case of Xmodem-1K the blocks 
are 1024 bytes.  Since Xmodem doesn't understand blocks of anything other 
than the standard size, communications programs have to add some sort of 
garbage data to the end of the file they send to pad the file out to a 
multiple of the standard block length.  There arcertain circumstances where 
this may make a difference in how the file is interpreted at the receive 
end.  For program execution, the extra characters will probably not matter, 
but other types of files may be adversely affected by this "rounding up."  
Both Kermit and Ymodem avoid the problem of rounding up files as well as 
the problem of needing to tell both ends of the transfer what file is being 
sent.  Both protocols also offer the ability to send multiple files in one 
transfer.  This is a terrific convenience since it allows you to specify a 
set of files to be transferred and then walk away and do something else 
while the files arsent.  In terms of speed, Ymodem has Kermit beat hands 
down.  Where Kermit excels is in moving files between dissimilar equipment.  
Kermit is probably not a very attractive option for transfers between the 
Braille 'n Speak and the PC, but it may be a good choice for other 
circumstances.

I hope this is a useful introduction to transfers of binary data between 
PC and Braille 'n Speak.  This ability to send any kind of file is a great 
help in making the best of one's existing equipment with a new Braille 'n 
Speak.