3
© Sealevel Systems, Inc. 7204 Manual | SL9061 7/2021
Introduction
The Sealevel Systems ULTRA 485+2.PCI
is a two channel PCI Bus serial I/O adapter for the PC and
compatibles and features the 16850 advanced UART. It provides two field selectable RS422/485 serial
ports supporting data rates up to 460.8K bps. The 16850 advanced UART provides a 128 byte FIFO that
helps reduce processor overhead by reducing the number of interrupts that need servicing. Each port can
be individually configured.
Choose the RS-422 mode for long distance device connections up to 4000ft. where noise immunity and
high data integrity are essential. Select RS-
485 and capture data from multiple peripherals in a RS485
multidrop network. Up to 31 RS-485 devices can be connected to each port to automate your data
collection. You can even mix the ports in any of the interface combinations to provide maximum flexibility
to your application.
In RS-422 mode, the card works seamlessly with the standard operating system serial driver. In RS-485
mode, our special auto-
enable feature allows the RS485 ports to be viewed by the operating system as a
COM: port. This allows the standard COM: driver to be utilized for RS485 communications. Our on
-board
hardware automatically handles the RS-485 driver enable.