Impulse 7203 - Manual (Page 11)

Technical Description
Sealevel Systems ULTRA COMM+2I.PCI Page 8
Technical Description
The Sealevel Systems ULTRA COMM+2I.PCI provides a PCI interface
adapter with 2 isolated asynchronous serial ports providing a versatile interface,
field selectable as RS-232 for modems, printers and plotters, as well as
RS-422/485 for industrial automation and control applications. Isolation is
important in installations where the equipment being connected to the PC is
either far from the PC, or on a different power transformer circuit. Ground loop
current is a commonly neglected and misunderstood phenomenon that leads to
data loss and the destruction of communications interfaces.
The ULTRA COMM+2I.PCI utilizes the 16C850 UART. This chip features
programmable baud rates, data format, interrupt control and industry leading
128-byte FIFOs.
Connector Pin Assignments
RS-232
Name Pin # Mode
TD Transmit Data 3 Output
RTS Request To Send 7 Output
GND Ground 5
RD Receive Data 2 Input
CTS Clear To Send 8 Input
Note: These assignments meet EIA/TIA/ANSI-574 DTE for DB-9 type
connectors.
RS-422/485
Signal Name Pin # Mode
GND Ground 5
TX + Transmit Data Positive 4 Output
TX- Transmit Data Negative 3 Output
RTS+ Request To Send Positive 6 Output
RTS- Request To Send Negative 7 Output
RX+ Receive Data Positive 1 Input
RX- Receive Data Negative 2 Input
CTS+ Clear To Send Positive 9 Input
CTS- Clear To Send Negative 8 Input