Developers guide

Chapter 14: Scanners
Overview
Psion Teklogix Mobile Devices SDK Developers Guide 85
14.1 Overview
The Mobile Devices SDK provides functions that handle all the low-level activities of bar code
scanners.
14.1.1 Types Of Scanners
The Mobile Devices SDK supports the following types of bar code scanner:
• Non-decoded scanners
• Decoded scanners
• Imaging scanners (for legacy applications only, see Section 14.1.1.3 below)
14.1.1.1 Non-decoded Scanners
Non-decoded scanners present unprocessed scan data to the computer. These scanners rely on the
computer to do the decoding. The Mobile Devices SDK returns the scan data as a character string
to the calling program.
The non-decoded scan driver receives scan data from the peripheral controller and decodes it. It
passes it to the Scan Control Service, which performs any necessary translations and delivers the
data, through the SDK, as a character string to the application.
14.1.1.2 Decoded Scanners
Decoded scanners have built in decoders; they process the raw scan data themselves. The format-
ted data is passed to the scanner driver; then to the Scan Control Service; then to the SDK; and
finally to the application. Both 1D and 2D decoded laser scanners are supported by the Mobile
Devices SDK. The data is received as an undelimited character string.
14.1.1.3 Imaging Scanners
The Mobile Devices SDK supports bar code scanning by legacy imagers; however, the Mobile
Devices SDK should not be used for new applications involving imagers.
An imaging scanner can take digital photographs in addition to scanning bar codes. The default
mode for an imaging scanner is to act as a decoded scanner. The Mobile Devices SDK provides
methods for putting an internal imaging scanner into image capture mode and returning it to bar
code scanning mode, as well as for controlling it in image capture mode. The SDK does not
control an externally connected imaging scanner when it is in imaging mode.
14.1.2 Scanner Connections
Scanners are connected to the computer in one of the following ways:
•Internal
• External through the tether port
• External through a vehicle-mount cradle
Important: New applications must use the Mobile Devices SDK for laser bar code scanners
only. The Imaging Services SDK must be used for all imaging scanner applica-
tions including reading bar codes.