Printer Buffer Size; Universal Serial Bus (Usb); Usb Support And Standards - TransAct POSjet 1500 Programmer's Manual

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Programmer' s Guide POSjet 1500 Port Protocols and
Connection Specifics

Printer Buffer Size

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The POSjet 1500 Printer has a configurable buffer size. It can be set from 40 to 8192 bytes. The configurable
buffer allows an application to control how far ahead the buffer gets from the printer. The smaller the buffer, the
tighter the control will be. It is up to the application developer to select the optimal buffer size. The default buffer
is 8192 bytes.

Universal Serial Bus (USB)

USB was originally conceived in the early 90's and officially recognized by Compaq, Intel, Microsoft and NEC.
The development of USB has been slow, however, with the release of Windows 95 SR2 development accelerated.
Windows 2000 now fully supports USB as do Windows 98 SE, and Windows Me. A technical discussion of USB is
beyond the scope of this document. If you would like more information about USB, visit the USB web site at
www.usb.org.

USB Support and Standards

POS printers are different from typical Windows printers in several ways. Microsoft has recognized these
differences and has been working with the USB Device Working Group to generate a set of standards that would
abstract all point-of-sale devices at the application level. At this time, a workable standard for POS is years away.
So while Microsoft is interested in POS in the long term, Microsoft's immediate goal is to enable POS USB devices
a way that is compatible with existing service objects.
In order to support USB POS devices under the existing software architecture, Microsoft is providing the POSUSB
driver model to allow USB POS devices to interface as serial COM ports to service object DLLs.
The TransAct USB Printer interface is based on this Microsoft POSUSB driver model. It provides full bi-directional
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interface to the printer and allows most existing applications to interface to the USB, Ithaca , POSjet 1500 as if it
were on a serial COM port. In addition to this, we have allowed the printer to register as a composite device. This
allows the printer to appear in the system as a USB print device as well as a COM port. If you are using a windows
printer driver (ours or the Generic driver) you can assign the printer to the USB port.
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We hope that supporting the USB POSjet 1500 as a composite device provides the best of both worlds to our
customer.
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The USB interface card that is used with the POSjet 1500 is designed with the Cypress Anchor Chips EZ-USB
chip. The Anchor Chips EZ-USB is a compact integrated circuit that provides a highly integrated solution for
implementing a USB peripheral device.
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