Getting a scanner to work with NT is easier when you follow these shortcuts
Scanners are important hardware items for many Windows NT sites, but
getting a scanner to work under NT can be a challenge. To do so, you need an
NT-compatible scanner, a SCSI host adapter, and the right drivers. After several
tries, I finally got my Hewlett-Packard (HP) ScanJet desktop scanner up and
running under Windows NT 3.51 and 4.0 (for more information about my hardware
setup, see "Author's System Configuration," page 137). Here, I explain
the procedure I used to install my scanner and provide tips you can apply to
running flatbed scanners (or other types of image scanners) in your NT shop.
Windows NT Compatibility
Flatbed scanners are scanners that have a flat glass surface on which you
place the object you want scanned. A reading head moves across the surface to
input information.
Currently, HP ScanJet scanners are the only flatbed scanners that Microsoft
officially supports (i.e., includes on the Hardware Compatibility List--HCL) for
Windows NT versions 3.51 and 4.0. However, several other flatbed scanners run
under NT 3.51 or 4.0, including Epson, Microtek, Xerox, and UMAX scanners.
According to users of these scanners, the manufacturers have developed the
appropriate drivers, making their installation under NT 3.51 and NT 4.0 fairly
straightforward.
SCSI Interface
To attach a scanner to an NT system, you first need a cable and a SCSI
interface, or host adapter. (You can't use a parallel port with NT. For
explanations of SCSI and other terms in this article, see "Glossary,"
page 134.) Although some motherboards include a built-in SCSI bus, most SCSI
interfaces take the form of a card that you insert into a spare expansion slot.
Microsoft has certified more than 100 SCSI adapters as compatible with NT 3.51
and 4.0, among them are products from Adaptec, BusLogic, and NCR. Again, check
the HCL for a complete list of supported SCSI adapters.
The Right Drivers
A driver is a program that controls a piece of hardware and lets it
exchange data with other hardware and software. A SCSI scanner usually needs two
drivers to work, or more likely, two sets of modular drivers and their
associated DLLs and system files. The host adapter driver is often called the
system-level driver; the scanner driver is usually called the source
driver. Make sure you have the latest versions of all required drivers.
Driver compatibility is a problem in the NT environment. For example, the
host adapter needs the correct driver to communicate with NT, the scanner needs
a driver to talk to the host adapter and to NT, and the drivers must work
together. In NT 3.51 and 4.0, Microsoft provides two HP ScanJet scanner drivers
similar to the original HP drivers. (Microsoft's developers customized the
original drivers for NT.) You'll want to use these Microsoft drivers, rather
than the original HP drivers, to ensure that your HP ScanJet scanner works hand
in hand with NT.
To further complicate matters, scanner application programs often have
modules to communicate with the scanner via the operating system and the host
adapter. Two main industry standards exist for image and scanner interfaces:
Image and Scanner Industry Standard (ISIS) and TWAIN. Many software developers
and scanner manufacturers have designed their application software, scanners,
and drivers to comply with one or both standards. TWAIN is more common than ISIS
for scanning products that work with NT. ISIS is more commonly used for
optical character recognition (OCR) packages. For example, Adobe's Photoshop and
Pictronics' IntelliScan (an image-scanning and editing package) are TWAIN
compliant. Pictronics claims its product supports all desktop scanners through
the TWAIN interface on NT. Be aware, however, that not all TWAIN software works
with NT; as mentioned earlier, you need the latest drivers. For example only
TWAIN 1.6-compliant programs, which include TWAIN_32 drivers (not the older
TWAIN32 modules), work with NT 3.51 and 4.0. Thus, Adobe Photoshop 3.0.5, which
uses the TWAIN_32 drivers, works with NT; however, version 3.0 doesn't work
because it uses the TWAIN32 drivers.