FILE NAME:          1 6 5 5 0 .R E F

Original DATE:      February 16, 1995

REVISE   DATE:      August 2, 1999

FROM:               Artic Technologies Help Center

                    Artic Technologies
                    1000 John R. Road
                    Suite 108
                    Troy, MI  48083.

                    (248) 588-7370 Extension 11 Sales
                    (248) 588-2650 Fax
                    (248) 588-1425 Help Center

                    www.artictech.com InterNet WEB Site

                    sales@artictech.com InterNet E-Mail Sales

                    help@artictech.com  InterNet E-Mail Help


TO:                 All Artic Users

Subject:            16550 U-ART.

     Here at Artic Technologies, we have been noticing that more
and more 80486 or Pentium computers have been sold with I/O
controllers which use 16550 serial U-ART chips.  

     One of the great benefits of this serial IC chip is its
ability to handle very fast data rates with no loss of data. 
This is accomplished via an on-chip serial buffer.  Some computer
users may know of this as a Com FIFO buffer.  FIFO stands for
"First In, First Out".

     When using screen reading software that is expecting
constant I/O from a serial speech synthesizer, the 16550 on-chip
buffering may slow up response or cause the whole computer system to
hang. 

     Why is this?  Many times, the computer's own CMOS program may
initialize the serial ports with the 16550 buffer on.  It appears
that the chip does not make available data until the FIFO buffer is
full.  Screen access software packages that look for constant
streams of index markers plus other synthesizer responses will have
to wait until the 16550 Com FIFO buffer gives it up.

     The solution is to turn off the buffer in the 16550 serial
port.   A utility called COMFIFO.COM is available from Compaq. 
Also there are two ZIP files that may be available from the Inter
Net. They are: 16550A.ZIP and 16550S13.ZIP.    You will need
PKZ204G.EXE utilities to unzip the files.

          All of the above three utilities have the same command
line options.

     [command] [com-number 1 through 4] [turn buffer ON/OFF]


     Example for using Compaq's COMFIFO program to turn off the
     16550 buffer for COM1:

          COMFIFO 1 OFF


     16550A.ZIP program.

     UN ZIP the file called 16550A.ZIP.  You will be left with
     two files: 16550A.EXE and 16550A.DOC.  Before you run your
     screen reading software, execute the 16550A.EXE program,
     followed by the port number and buffer [OFF/ON] switch.

     Example for using 16550A.EXE to turn off buffer for COM1:

     16550A 1 OFF


     16550S13.ZIP program.

     UN ZIP the file called 16550A.ZIP.  You will be concerned
     with two files: 16550_T.EXE and 16550.DOC.  Before you run
     your screen reading software, execute the 16550_T.EXE
     program, followed by the port number and buffer [OFF/ON] switch.

     Example for using 16550_T.EXE to turn off buffer for COM1:

     16550_T 1 OFF

     Here at Artic, we can not guaranty how well the programs will
work with all screen reading software or 16550 serial port chips. 
It is something to try when your computer and synthesizer hangs
after a short period of time.

     Also, we are looking at making available 16550A.ZIP and
16550S13.ZIP to all users of the Artic Technologies BBS.

Dave Barber -- Artic Technical Support: 248 588 1424.\