/FHQ25: My {9600 or greater} BPS modem drops characters under DESQview.  Is high
speed communication possible under DESQview?/FB



Yes, high speed communication is possible.  First, you must go into the
DESQview setup program and set ``Optimize Communications'' to Y /JB(see Q29)/q29.txt/.  If you still lose characters, you may have to get a new serial
board.  The characters are coming in too fast for DESQview and your
communications program to process them.



The chip that controls serial communication is known by many names.  On
an XT (or an 8-bit I//O board) it is an 8250.  Most ATs contain the
16450. The problem with these chips is that they can only buffer one
character at a time, so if DESQview doesn't allow your communications
program to respond fast enough, you'll lose that character.



The solution is to get a board with the National Semiconductor NS16550AN
or NS16550AFT chip.  This chip buffers up to 16 characters, so character
loss is less likely to occur.  If you are the handy type, you can even
swap your 8250 (or whatever) for the NS16550AN yourself, for the chips
are pin-compatible.



Do not get a 16550 non-A chip.  It is an old, buggy chip.  Also, Western
Digital makes a 16550 which is rumored to be buggy at speeds of 2400 BPS
or less.