Instruction Manual

Technical Description
Sealevel Systems ULTRA 485.PCI Page 9
Technical Description
The Sealevel Systems ULTRA 485.PCI provides an additional asynchronous serial port, field selectable as
RS-422/485/530 for industrial automation and control applications.
The ULTRA 485.PCI utilizes the EXAR 16C850 UART. This chip features programmable baud rates, data format,
interrupt control and an industry leading 128 byte FIFOs.
Connector Pin Assignments
RS-422/485/530 Pin Assignments (DB-25 Male DTE)
Signal Name Pin # Mode
GND Ground 7
RDB RX+ Receive Positive 16 Input
RDA RX- Receive Negative 3 Input
CTSB CTS+ Clear To Send Positive 13 Input
CTSA CTS- Clear To Send Negative 5 Input
TDB TX+ Transmit Positive 14 Output
TDA TX- Transmit Negative 2 Output
RTSB RTS+ Request To Send Positive 19 Output
RTSA RTS- Request To Send Negative 4 Output
Note: These assignments meet the EIA/TIA/ANSI-530 DTE.