2. You Need The Following Components

HP's Ipaq hx4700

For the test THG used the Ipaq hx4700 , a business PDA equipped with standard wireless functions.

We need the device's integrated WLAN module to connect the PDA wirelessly with the network. That's because the actual phone connection via IP to the Internet will later be made by the WLAN's access point, or rather, by the network supporting it. To provide the necessary bandwidth for voice transmission, a broadband connection is required for the Internet connection, and the PDA's CPU must run at 400 MHz or more. After all, the CPU has to be able to handle the highly computation-intensive voice encoding and decoding functions itself, pretty much in real time. We used the WG602 from Netgear as our WLAN access point.

The Ipaq hx4700 has an integrated WLAN and Bluetooth module

A Bluetooth headset serves as a receiver. It is connected to the PDA through the integrated Bluetooth adapter.

Mobile Bluetooth headset from Logitech

To transform our Pocket PC into a cell phone, we used Skype for Pocket PC . In very general terms, the client application Skype works as a kind of mobile voice over IP gateway, also called a "soft phone." This application adds the function of a mobile phone to the PDA.