Portable Radio Frequency-Identification (RFID) readers are often used to identify objects which have an RFID tag attached. The portable RFID readers offer advantages over traditional laser barcode scanners because they can identify many objects more or less simultaneously, and can also identify objects upon which the tag has been obscured from view. It is possible to identify objects more rapidly using a portable RFID reader in place of a laser barcode scanner because the operator does not have to spend time accurately aiming the device.
However, if the operator of the RFID reader needs to read only a tag attached to a specific object, it is required to adjust the read range of the RFID reader. Reducing the read range can allow the reader to read a tag attached to an object from a short read range so that only the object directly in front of the portable RFID reader's antenna is read. It is possible to control the read range of the RFID reader by, for example, reducing or increasing the power of the RF field. This is usually achieved by interacting with a device for controlling the RFID reader in a time consuming way, such as selecting actions from a menu using a touch screen, or using a keypad on the device to change the configuration. Such an interruption to the work flow is frustrating to the operator of the device, and wastes valuable time. Thus, there is a demand from consumers to be able to easily switch between a long range operation and a short range operation.
Operating a portable RFID reader at a short range has problems associated with it in that the ability to read an RFID tag is effected by the object to which the tag is attached. If the RFID tag is attached to an object that has a high liquid content, then the RF field is absorbed. If the RFID tag is attached to an object with a high metal content, the RF field is reflected, which causes distortions and fading of the RF signal. Both of these effects make it more difficult to read the RFID tag. Different amounts of RF power are therefore required to read similar RFID rags at the same range, depending on the type of object they are attached to. If an operator is required to read a number of RFID tags, each fixed to an object of a different metal or water content, but read each tag individually, the operator may spend a large amount of time re-configuring the RF output power of the device, rather than reading tags.
Therefore, there is a need for a handheld terminal that allows a user to easily control the read range of an RFID reader while the user operates the RFID reader.