
                   DECtalk PC Multi-board.

MULTI-BOARD SUPPORT.

In V4.1 and higher, a multi-threaded support has been implemented and
four (4) DECtalk PC boards can now co-exist in one system. 
This will be useful in the development of multi-line 
telephone-based applications.

     Number of Boards.

The limitation on the number of boards is based on (a)
number of available slots in the PC (upto 4); and (b) the
number of I/O addresses.  The switchpack currently in use
allows for two switches (4 positions) for I/O addresses.
Thus, the maximum number of boards currently allowed is 4.

Changing Switch Settings.

 Place the board on a flat surface with the bus-connector to
your lower right. The bank of DIP-switches is 1 inch long by
1/3 of an inch deep and is located in the lower right-hand
corner of the card. There are 9 switches arranged in a
horizontal row with switch 1 to the left and switch 9 to the
right.  Switches set to the UP position are ON with UP begin
towards the center of the card away from the lower edge.
Switches 6 and 7 are the ones that select the I/O address.

The Dip Switches on the DECtalk PC board, must match the base 
I/O address you are using.

Switches 1 through 5 and 8 through 9 should always be turned off.

Switches:	I/O Base Address:

6      7	address.

OFF   OFF	240.

On    OFF	250.

OFF   On	340.

OFF   OFF	350.



     Loading Multi-Boards.

 The command MT.BAT will load all the necessary files onto
each board. The BAT file called MT.BAT is set up to load two
boards. If you want to load more than two boards the file
MT.BAT will need to be edited. This file as the line:

DT_CONF
DT_DRIV -c -b240 -b 350
DT_LOAD -M 0 KERNEL.SYS DTPC.DIC LTS.EXE PH.EXE CMD.EXE USA.EXE.
DT_LOAD -M 1 KERNEL.SYS DTPC.DIC LTS.EXE PH.EXE CMD.EXE USA.EXE.

 The boards are numbered 0 through 3.


     Program Calls.

The lowest numbered I/O address of board is module 0. The
next lowest is module 1, and so on. In multiboard mode,
register SI indicates which module  you wish to communicate
with on all program calls and it must be specified if there
is more than one board installed. If there is exactly one
board in the system, SI is ignored. To determine the number
of boards in the system, use the GET_STATUS call which
returns the number of installed boards in SI.

Note: In multiboard operation, the DT_LOAD
commands require an additional argument (-m D where D = 1-4)
which specifies the appropriate board.

 In order to run the DECtalk PC multi-board test from the
DOS prompt you need to use the command MUL_READ.EXE. The I/O
address for the boards must be different for each of the
modules used. In order to changes this you must changes the
switch setting on SW1.

To demonstrate the use of more than one board, type mul_read
(for multi-line) followed by -m, the module number and the
file name. For example:

     mul_read -m 0 (filenamex), -m 1 (filenamey) -m 2.

The above comand would allow three separate files to be read
from three boards.

Note: There are no on-board telephonics on the DECtalk
board. DECtalk could be combined with telephonics cards
available from a number of vendors. Software to interface
the DECtalk board with a telephonics card is the
responsibility of the application.


     
     MUL_READ.EXE Command.

The format used for this command is as follows:

     MUL_READ -m <board number> <file name>

The boards are numbered 0 through 3. Four board are the
maximum number boards you can run in your PC at any time.
