JI> The problem seems to be that when DTE is set at over 115200bps, some of
 JI> received data will be missing for sure and halves the 
 JI> CPS. So is there any cure for this kind of problem?
What is the trigger setting of the uart. At 115200 and above, it should be 
set at 8, 4, or even 1. Are you sure the 16C650 works with your software?
You might check some of this;
CRC errors are generally caused by lack of the CPU to respond to an
interrupt request in time. This can be caused by several things including,
slow clock speed, too many other IRQ's to service, multitasking, improper
cable, improper program configuration, etc.
Software configuration;
        HS modems require things to be right to function properly. Most
software (terminal) programs have options for RTS/CTS (hardware) flow
control. Use this, and turn XON/XOFF OFF. 
        Most also have something called Autobaud, or Locked Baud rate,
etc. Autobaud should be turned off, and the baud rate should be locked
at a minimum at the next speed higher than your modem supports (higher
if possible). For v.32/bis modems, the minimum should be locked at 19200.
For v.34/vfc modems, the minimum should be locked at 38400.
Uarts;
        Although you may be able to get by without a buffered uart, it is
likely to cause you problems at one time or another. A buffered uart
(16550 or equiv.) is almost always needed for reliable HS communications
between the modem and the computer. If you don't have a buffered uart,
get one. Internal modems have the uart built on the board. Never buy
an internal modem without a buffered uart, or equiv. When using an
external modem, the uart is on your serial card, motherboard, or IDE
controller combo. WARNING. Most IDE controllers DON'T come with a 
buffered uart. IMPORTANT. Set the uart trigger. A setting of 4 should
work in all but the most demanding situations. Most software defaults
this setting to 14. You may need to change it under multitasking, high
IRQ stuations, or a slow cpu clock speed.
Cables (external modems only);
        I have seen many cables that were wired improperly, right from
the manufacturer. So you may want to check these too. Any decent modem
manual will have the pinouts listed.
Non buffered uarts (16450, 16452, 8250, 83450, etc., etc.);
        A 16550 uart is pin compatible with all the above and more, with
the exception of the 16452 (a dual port uart), and a few other similar
models. If you can't replace your uart with a buffered one, then remove
any TSR's, device drivers, etc. that may need cpu time. If you have plenty
of ram, try downloading to a ramdisk. You should also set your locked baud 
rate to the lowest possibly (and still be higher than your top modem speed).
Hope this helps someone.
--- Maximus/2 3.00
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