1. Touch screen
PDAs in the past such as the Apple Newton and the Palm Pilot featured touch screens for user interaction, there are few buttons as shortcuts for programs you often use. Touch screen PDAs, including Windows Pocket PC devices, usually have a detachable stylus that can be used on the touch screen. Interaction now can be done by touching the screen to activate buttons or menu choices, and dragging the stylus to highlight or etc.
2. Memory cards
Many PDAs in the past did not have memory card slots. Currently, however, most PDAs provide both an SD (Secure Digital) and a Compact Flash cards for Wi-Fi and Webcams Some. Furthermore, PDAs also provide USB port for USB flash drives.
3. Wired connectivity
Currently, many PDAs connect via USB cable instead of serial ports or other proprietary format as in the past. This helped connect to a computer, and few, if any PDAs were able to connect to each other by using cables, as USB requires one machine to act as a host to functional which was not often planned. Some PDAs were able to connect to the Internet
4. Wireless connectivity
Most modern PDAs can use Bluetooth wireless which is a popular tool for mobile devices. Moreover, it also can be used to connect keyboards, headsets, GPS and many other accessories, as well as sending files between PDAs. Many mid-range and superior PDAs have Wi-Fi/WLAN/802.11-connectivity, used for connecting to Wi-Fi hotspots or wireless networks
5. Synchronization
One essential function of PDAs is synchronizing data with a PC. This allows up-to-date contact information stored on software such as Microsoft Outlook or ACT! to keep the database on the PDA up to date. The data synchronization helps ensure that the PDA has an accurate list of contacts whether or not, ensure appointments and e-mail, and allow users to access the same information on the PDA which is acting like a host computer.
