A portable data terminal, or shortly PDT, is an electronic device that is used to enter or retrieve data via wireless transmission (WLAN or WWAN). They can also serve as barcode readers, and they are used in large stores, warehouses, hospitals, or in the field, to access a database from a remote location.
PDT's frequently run wireless device management software that allows them to interact with a database or software application hosted on a server or mainframe computer.
References
Portable data terminal Wikipedia(Text) CC BY-SA