Pocket PC phone edition device made by HTC from Taiwan. Also known as O2 XDA, T-Mobile MDA, Siemens SX-56, Qtek 1010 and a few lesser known brand names.
PocketPC, 320x240 pixel screen at 4096 colors. StrongARM processor at 200 MHz, 32 or 64 MB RAM, 32 MB ROM
The model number (printed on the back) is PW10, followed by an 'A' for the 900/1800 version, and a 'B' for the 900/1900 version. Then there's a digit which is usually '1', except for the T-Mobile MDA.
Currently no longer in production, this phone has been superseded by the Himalaya.