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I.
GENERAL INFORMATION
The Quatech, Inc. ES-100M provides eight RS-232 asynchronous
serial communication interfaces for IBM-compatible personal computer
systems using the 16-bit ISA (Industry Standard Architecture) expansion
bus. The QS-100M is a four-port version of the same product (with
several blank areas on the circuit card). External connections are made
using RJ-11 "phone jack" connectors. This document uses "QS/ES-100M"
when information applies to either product.
The QS/ES-100M's serial ports are implemented using 16450
Universal Asynchronous Receiver/Transmitters (UARTs). For higher
performance, 16550 UARTs can be installed in place of the 16450 UARTs.
The 16550 contains a hardware buffer that reduces processing overhead.
Software must be aware of the 16550 UART for the device's extra
capabilities to be used, otherwise it will act as a 16450 UART. The 16550 is
suggested for multitasking environments and for applications involving
high data rates.
The QS/ES-100M is highly flexible with respect to addressing and
interrupt level use. The serial ports are addressed in a contiguous block
that can be placed anywhere within the range of 0000 hex to FFFF hex,
and available interrupt levels include IRQ2 to IRQ7, IRQ10 to IRQ12,
IRQ14, or IRQ15. (Early versions of the QS/ES-100M are limited to
IRQ2-7.)
All ports on the QS/ES-100M share one interrupt level. A special
interrupt status register is provided to allow controlling software to
manage the shared interrupt level. The shared interrupt feature
minimizes the system resources consumed by the adapter.
In order to support the use of the shared interrupt feature of the
QS/ES-100M, Quatech has developed device drivers for several popular
operating systems and environments. The sales department can be
contacted for details on current offerings.
Quatech QS-100M/ES-100M User's Manual
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