I run a two node PCBoard 12.1 system on a Mylex 386 under Desqview 
with a USRobotics HST modem.  I open my com port at 19200.

I found that under this configuration, uploads to the board at 19200 
abort.

The way I was able to solve the problem was to take Chuck Foresberg's 
advice in DSZ.DOC:

" Switching to a National 16550A UART chip helps tremendously, allowing
 transfers at 115200 bps instead of 9600 bps with a standard 8250.  Arrow
 Electronics 1-800-932-7769 sells National NS16550AN chips mail order
 (credit card) for about $22 each in small quantities."

After getting the new chip, I simply popped out the old 16450 and 
plugged in the 16550A.  Nothing to it.

The next thing is to replace PCboard's Ymodem-G
with DSZ's "Qmodem-G".  You MUST be running a registered
version of DSZ to enable the full flow protocols.  Sysops can register 
for free by agreeing to certain terms in the DSZ.DOC.

Change the Ymodem-G entry in PCBPROT.DAT to look like this:


G,S,1024,Ymodem-G


Then add the following two .BAT files to your \PCB directory:

PCBRG.BAT:
----------

echo off
echo *** Function Keys Disabled During DSZ Operation! ***
if exist pcberr.fil del pcberr.fil
set DSZLOG=YMODEMG.LOG
dsz pB4096 handshake both rx -c -k -g %3
if errorlevel 1 goto bad
goto end
:bad
copy pcberr.old pcberr.fil
:end
echo on


PCBSG.BAT:
----------

echo off
echo *** Function Keys Disabled During DSZ Operation! ***
if exist pcberr.fil del pcberr.fil
SET DSZLOG=YMODEMG.LOG
dsz pB4096 handshake both sx -k -g %3
if errorlevel 1 goto bad
goto end
:bad
copy pcberr.old pcberr.fil
:end
echo on


The lines that say SET DSZLOG=YMODEMG.LOG will tell DSZ to write 
information on each transfer to a file called YMODEMG.LOG.  This way 
you can monitor the Ymodem-G transfers, as external protocols on the 
main board won't write the cps to the CALLER file.  Here is what my 
YMODEMG.LOG looks like:


S 131072 19200 bps 1140 cps   0 errors    27 1024 D:\PCB\UP\ANSIVIEW.ARC -1
S  36864 19200 bps 1117 cps   0 errors     7 1024 D:\D1B\EXOTIC.ARC -1
S  95232 19200 bps 1120 cps   0 errors    18 1024 F:\D4\GUPPIES.ARC -1
S  56320 19200 bps 1149 cps   0 errors    15 1024 D:\PCB\UP\CHKUP17.ARC -1
S  15360 19200 bps 1182 cps   0 errors     2 1024 D:\PCB\UP\SOCAL047.ARC -1
S  20480 19200 bps 1138 cps   0 errors     3 1024 D:\PCB\UP\FRAGS11.ARC -1
S  52224 19200 bps 1135 cps   0 errors    13 1024 D:\PCB\UP\CARLOG.ARC -1
S 109568 19200 bps 1130 cps   0 errors    33 1024 D:\PCB\UP\REALTY.ARC -1

            cps:   ^^^^^^^

DSZ's Qmodem-G is fully compatible with Qmodem's Ymodem-G.  The user 
will not be able to tell the diference between DSZ and PCBoard's 
implementation.


Good luck!

-Joseph Sheppard
 The Ledge PCBoard
 (818) 352-3620