UltraPort Serial Adaptors User Guide
Installing under Windows 2000/XP/Server 2003/Vista/Server 2008
Page 40
Chapter 2 Installing drivers and host cards
9. If the COM port belongs to a UltraPort SI card then you can click on the
Advanced
button
to access the software switchable interface modes as shown in the next diagram.
Protocol Type:
The valid software switchable protocol types are EIA-232, EIA-422, EIA-485 Full
Duplex and EIA-485 Half Duplex. Each port on the UltraPort SI are independent of each other and
therefore you may select different protocols per serial port.
Baud Rate Multiplier:
The baud rate multiplier allows the user to multiply the configured baud rate by
1, 2, 4, 8,16 or 32, hence achieving greater speeds on the UltraPort SI serial interfaces. This is
applicable for each protocol type selected. Baud rates for EIA-232 are up to 921.6 Kbps per serial
port. Baud rates for EIA-422/EIA-485 are up to 3.686 Mbps per serial port.
Slew Rate Limiting:
The default setting for slew rate limiting is disabled. This will allow higher baud
rate speeds on each EIA interface port. Slew rate limiting enabled, minimizes EMI and reduces
reflections caused by improperly terminated cables. Operation in slew rate limited mode reduces the
amplitudes of high-frequency harmonics.
Line Termination:
The line termination parameter is not changeable by the user in EIA-232
mode. However both EIA-422 and EIA-485 modes are defaulted to disabled but can be
enabled by the user if needed.
