Elo TouchSystems 1525L manual Typical Operation, Open a device, Query the device’s capabilities

Section 1. Overview

TYPICAL OPERATION

This section describes a typical pattern that an application developer may use to operate a device. Although it is the most typical pattern, it is by no means the only viable one. Refer to Section 5, Example Applications, to see how to use the drivers in various applications.

Open a device

Access to the device is obtained by opening the comxx: port that the device was installed as.

This is not the hardware port that the device may be attached to, but a virtual comxx : port presented by the driver (e.g., COM5 or higher). A handle is returned by the open function and is required for all subsequent interactions with the driver. When opened, the driver initializes itself and, where required, the device.

Some drivers support automatic settings. In this mode, the driver first attempts to communicate with the device at the previous setting or at the default setting if it is the first time. (The setting for the initial attempt is grayed out in the manual settings fields.) If the driver does not receive a response, it will adjust the settings and try again. This sequence continues until the device responds or until all possible settings have been attempted.

If the driver is set for the automatic mode, it may take considerably longer for the device driver to detect an error. In particular, if the device is not connected to the specified port or if its power is off, the device driver may take several seconds attempting all possible settings before it returns an error. The application program should be tolerant of this delay.

Query the device’s capabilities

The application now queries the device to determine if it can perform the required task. The capability properties (c_xxx) are provided for this purpose. For example, if an application requires the ability to read checks, it can get the c_check property to determine if the device can read checks.

Prepare the device for work

The device is prepared for operation by setting one or more of the configuration properties. Its mode of operation and other features are set up by these properties. Setting the capitalize property to 1 to cause all data written to or read from a card’s magnetic strip to be capitalized is an example of this type of initialization. In some cases, modifying a property may cause the driver to execute functions on the device.

Use the device

The device is now fully initialized ready for operation. Because most tasks with the device require interaction with the user, the application operates the device using primarily the interactive commands. A typical scenario is when, in response to some event, the user is prompted to swipe a card by using the display command, followed by a read command to

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