NCR 7169, Руководство пользователя

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1-14 NCR 7169 Multifunction Printer
About the Universal Serial Bus
The Universal Serial Bus (USB) is a peripheral bus for personal computers that was first
released in January 1996. Since that time, virtually all Intel Architecture personal
computers have the hardware to support USB, and a large number of computers exist
that have both the hardware and software support required to interface with USB
peripherals.
Advantages of USB connections
USB has a number of advantages over legacy connection schemes, for example, the
serial RS-232. These advantages include:
• High speed: up to 12 MB/second for high-speed devices.
• Plug and play: Devices are automatically recognized and configured at installation.
• Hot plug: Bus supports installation and removal of devices with the power applied.
• Up to 127 devices: One host can support up to 127 devices with the use of hubs.
• “Free ports”: Most PC architecture machines contain two USB ports in the base
hardware.
These advantages have become attractive to the POS industry for a couple of reasons.
Additional POS devices
Some POS systems are required to host more peripherals than can be supported by two
RS-232 ports typical in a platform. With the addition of one or two USB connectors, the
platform can support the additional devices that had previously required a serial port
expander card.
Higher bandwidths
New devices coming into use have bandwidth requirements that are higher than the
bandwidth that can be supported on legacy interfaces. As the speed and capability of
POS printers increases, the performance of the printer in an application can become
limited by the speed of the communications interface. USB provides ample bandwidth
to support current and future POS printer requirements.
Advantages of the NCR USB solution
NCR has eliminated any cost associated with porting applications to USB by
implementing a USB solution that simulates standard serial communications in
Windows 98 (SR2), NT 4.0 (Service Pack 3 or higher) and Windows 2000. Application
developers need only redirect their software to the virtual serial ports created by the
NCR USB solution to use the printer.