Specifications

20
THEORY OF OPERATION
General Overview
The IS4920 is a small area imaging barcode scanning engine designed for
integration into handheld portable data terminals or other OEM devices
specifically for the barcode scanning and/or OCR applications. The IS4920
functions like a digital camera and increases functionality and value to an OEM
product by adding additional capabilities such as digital image capture, decoding
of all standard 1D & 2D barcodes, reading OCR fonts, document lift, signature
capture, etc.
The IS4920 scanning engine consists of two main system components: the
miniature IS4910 imaging engine, which utilizes a high-resolution CMOS image
sensor, and a small decode board that contains a powerful microprocessor and
the firmware to control all aspects of the engine’s operations and provide a
means of communication with the host system over the standard set of
communication interfaces.
The model IS4920-xx103 provides communication with the host system over
TTL-level RS232 communication interface. Contact a customer service
representative at 1-800-ID-METRO or 1-800-436-3876 for availability.
The model IS4920-xx38 provides communication with the host system over
USB. It can be configured for the following protocols of USB communication:
• USB Keyboard Emulation Mode (default)
• USB Serial Emulation Mode
The system hardware architecture of the IS4920 scanning engine is shown on
the figure below.
Figure 13. IS4920 System Architecture