Kontron PCI-COM422, User Manual

Page: 16 / 36

page 16 PCI-COM422 User’s Guide
Baud Rate Ranges
The card has capability for two baud rate range selections and can be selected through
the setting of the CLK X1/CLK X4 jumper. The baud rates are selected on a port-by-port
basis. One range is for up to 115,200 baud applications and the other is up to 921,600
baud applications. The lower baud rate is selected when the jumper is in the CLK X1
position. When the jumper is in the X1 position we can utilize the industry standard baud
rate selection methodology. When in the X4 position, we must compensate for the new
input frequency by letting the Windows operating system see the frequency at 1/4 of the
selected value.
As an example when the X4 position is selected, assume the selected baud output is to
be 9600 baud. The operating system would need to have defined the value of 2400
baud so that the correct system operations occur.
Note: Refer to the Baud Rate Divisor Value Table in the chapter on Programming in this
manual.