Barcode Education

Historically, RF programming has been an expensive service to end users. Surprisingly, RF programming is relatively simple. The fundamental concept not to be overlooked is that RF terminals have a bounded display that need to be mapped to ÒhostÓ screens and that keyboards need to be mapped to ÒhostÓ databases. There are three ways of performing this: (1) screen remapping, (2) screen scraping, and (3) direct data access. In all of these cases, the RF terminal communicates to a device (usually a PC) which in turn communicates to a host screen or database.

Screen Remapping involves changing the host screens to be the same bounded size as the RF terminal display. The RF terminal then becomes a wireless display and wireless keyboard to the new host screens. The disadvantage of screen remapping is that a programmer must rewrite the existing host screens. Besides the time that this can take, the host source code is not always available. The advantage is that it is easy to modify the software and can be written fairly quickly.

Screen Scraping is a technique that will work with existing screens and existing applications. Input from the PDT is piped directly to an existing application. The software reads specific sections of the screen and sends it back to the RF terminal. The software acts as a referee between the bounded RF display and keyboard to the enlarged host display and keyboard. The disadvantage with screen scraping is slower response times and the user is tied to existing host screens. If host screens are changed, the screen scraping software will also need to change. The advantage of screen scraping is that no host modification is necessary. In essence, the user is adding a wireless keyboard and wireless display to an existing setup.

Direct Data Access communicates directly with the existing database(s). For example, if a user wants to check inventory, the program interacts with the inventory database and verifies the inventory level. The disadvantage is that users may not be sufficiently familiar with the structure of the database to access it directly. The advantage of direct data access is that it produces the fastest access of all three methods. Most PC programming languages can easily access other databases. Modifying screens to remap or to screen scrape is usually more difficult with most PC programming languages.