VT100.100 is a program designed to emulate a 24x80 full screen terminal.  
Two different brands of terminal protocols are supported:  Dec VT100 and 
ADM models 2, 3, 31 and 32.

    It does this by trapping the protocol control codes to modify a RAM 
simulation of the terminal screen.  The LCD of the M100 is used as a window 
into the larger screen stored in RAM.

    The program remembers where the cursor is located even if the window 
is positioned over a different portion of the RAM screen.  The window will 
home in on the cursor when F5 is pressed or any other key is pressed to enter 
data.  As data is entered, if the next data character is located outside the 
limits of the LCD window the display will automatically home in on the new 
cursor location.

    Due to the size limitations of the LCD, the display will tend to become 
very jumbled as the host transmitts a screen to the M100.  This is not a bug 
in the program, but a design feature so that you can tell when the host has 
completed its transmission.  Attempting to "view" the screen before the host 
completes transmitting can result in losing characters.  Upon termination 
of the host transmission the function keys can be used to de-jumble the LCD 
display.

    The following describes use of the function keys:


KEY   Description
---   -----------

F1    Display lines  1-8  columns 1-40
F2    Display lines  9-16 columns 1-40
F3    Display lines 17-24 columns 1-40
F4    Shift display 40 columns (left or right)

F5    Home window on current cursor location
F6    Print the RAM screen
F7    Not used  (see programming notes)
F8    Disconnect phone and return to MENU


    After you customize the program for your own use the program is very 
easy to use and quite capable of keeping up with the host at 300 baud.  It 
should be noted, however, because the program is written in BASIC an external 
modem at a higher baud rate would be wasted.


PROGRAMMING NOTES:

    The variables IX and IY contain the current cursor location.  KX and 
KY are the location of the LCD window.  String EA is used to detect the use of 
the cursors, TAB, BKSP, DEL and other special control codes.  EB translates 
the detected character to the proper control code.

    IE is a switch indicating that CHR$(27) has been detected.  EY is the 
control character that indicates cursor positioning data follows.  EJ is the 
control code for erase to end of screen from current cursor location.

    PH$ is the string used to hold the host phone number for the autodial 
ROM routine.

    Lines 124-134 and 164-172 may be deleted as they are specific to my 
host environment.  PH$ is initialized at line 118 to send a CR on carrier 
detect to cause my host modem to shift down to 300 baud.  You may want to 
change this to some other character sequence for you application.  NOTE: 
do not send anything that would cause the host to transmit characters until 
program initialization is complete at line 174.  The ROM routine lockup if 
too many characters are recieved because there is no input buffer until the 
dial operation is complete.

    Line 140 should be modified with you host system phone number.  Lines 
152-155 contain the MDM stat parms.

    Line 102 was included so that you can define an operation for F7.  The 
current instruction sequence is essentially a no-operation.