Quatech RS-422 - Manual (Page 6)

1 General Information
The Quatech, Inc. DSCLP-200/300(two-port) and SSCLP-200/300
(one-port) provides upto provides two RS-422 or RS-485 asynchronous serial
communication interfaces for IBM-compatible personal computer systems using the
PCI expansion bus. The DSCLP-200/300 uses Quatech's new Enhanced Serial
Adapter design. Legacy serial port data rates are limited to a maximum of 115,200 bits
per second. Quatech Enhanced Serial Adapters can achieve data rates as high as
460,800 bits per second. This discussion relates to DSCLP-200/300. A
SSCLP-200/300 is just one port in the discussion.
As a PCI device, the DSCLP-200/300 requires no hardware configuration.
The card is automatically configured by the computer's BIOS or operating system. The
two serial ports share a single interrupt line and are addressed in a contiguous block of
16 bytes. A special interrupt status register is provided to help software to manage the
shared interrupt.
The DSCLP-200/300's serial ports are implemented using 16550 Universal
Asynchronous Receiver/Transmitters (UARTs). These UARTs contain hardware
buffers (FIFOs) which reduce processing overhead and allow higher data rates to be
achieved. The 16550 contains a 16-byte FIFO and can transmit and receive data at a
rate of up to 230,400 bits per second.
The DSCLP-200/300 is supported under several popular operating systems
and environments. Contact the sales department for details on current software
offerings. Most device drivers are available for download from the Quatech world wide
web site at http://www.quatech.com.
DSCLP-200/300 User's Manual 1