All the PCI-Based PC Compatibility Cards are limited to 19,200 bps serial port speeds when using MS-DOS or Windows. However, testing has shown that 9600 bps is the maximum speed you should expect while maintaining the most reliable connection.
This limitation is the result of the UARTS used, lack of hardware handshaking in the PC enviorment, and other design factors.
In the Mac OS you do not have these same limitiations.
Article Change History:
12 Mar 1997 - Added reliable connection information.