Specifications

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Application Examples
Quatech's extensive data communication line is designed to
provide solutions for a wide range of serial and parallel
applications. The examples which follow are drawn from real-
life systems implemented with Quatech products. These examples
are by no means exhaustive, but are merely meant to illustrate
how our cards fit into different categories of data communication
applications.
If after reading this introduction and perusing product
specifications you are still not sure of an appropriate choice, feel
free to call one of Quatech's expert sales engineers to discuss
your application. We are always available to help you, and if
necessary, to suggest custom card configurations which may meet
your needs better than our standard product line.
Desktop Applications
Adding Serial Peripherals
While it may seem obvious, Quatech serial communication boards
can be used for adding additional serial ports to a desktop
computer. Our multi-port serial boards can be used to connect
digital cameras, serial modems, mice, plotters, serial printers, or a
wide variety of data acquisition and signal conditioning equipment
designed to run on a serial interface.
Serial data transfer is the communication backbone for the majority
of today's applications. Quatech asynchronous serial products
are available with up to eight ports on a single card, and are an
ideal solution for multi-port systems in numerous applications
including:
•Office Automation
•Banking Teller Networks
•POS Systems
•Navigation Systems
•RS-232 Networks (LAN Link, Easy Link)
•Low Cost Multi-Drop Networks
•Multiuser Systems
•Bulletin Board Systems
•Factory Automation
•Process Control
•Testing Systems
•Security Systems
•PBX Systems
Point of Sale Systems
Quatech RS-422 serial boards are currently being used to
implement Point-of-Sale (POS) systems in retail outlets throughout
the world. The Quatech board is used as the communication
link between a host computer and a network of cash registers
and coupon printers. RS-422 boards were chosen for this
application because of the long-distance serial link needed
(signals in an RS-422 network can be transmitted over 4,000
feet). In addition, the multi-point communication capabilities of
RS-422 were desirable because a single COM line could be used
to control 10 separate devices. Using one of Quatech's four-
port serial boards permits a single card to control up to 40 devices
(20 coupon printers and 20 registers)--more than enough for
the average store. For simplicity, RS-422 was employed because
the individual peripherals needed only to communicate with the
master, not with each other. (Had all points in the system needed
to talk to each other, then RS-485 would have been the better
choice, even though implementing the system would have cost
more.)
A typical point-of-sale system is pictured above. The PC contains
all the data needed by individual registers and coupon printers
throughout a retail location. Quatech PCI or ISA asynchronous
RS-422 serial boards are installed in PC expansion slots. The
number of expansion slots available in a system will vary with
each PC. RS-422 cables are run between the adapter and the
individual serial printers and serial registers. The cashier presses
buttons on the register which transmit the item purchased to the
host computer through one serial line, the host then returns the
appropriate price to the register so it can be displayed for the
customer. The host also checks the purchase against a file of
potential coupons, and if the purchase qualifies for a special
offer, the host sends the printer instructions to print a particular
coupon. (A similar system could also be implemented using a
serial bar code reader instead of or in conjunction with a register.)
(Point-of-Sale System)
Desktop/PC-Server with Pricing information,
Coupon triggers, etc.
Quatech 4-Port QSC-200/300
RS-422/485 PCI Card
Up to 20 cash register-coupon printer sets per four port card
Application Examples