HP released an Customer Advisory on the H5450, pointing out it is not capable of connecting to a WLAN AP that supports both 802.11b and 802.11g.
The integrated WLAN module inside your iPAQ Pocket PC allows connections up to 11 mbps (802.11b), but not higher. The technology associated with 802.11g allows for connection throughput higher than 11mbps.
You may notice that the Access Point ID field in the WLAN Status window will alternate between Scanning/Joining/Authenticating in an endless loop and never establish a connection.
Currently, the iPAQ Pocket PC h5400 Series does not support connectivity with WLAN Access Points that incorporate both 802.11b and 802.11g technology.
HP is developing a WLAN Firmware Upgrade that will allow your iPAQ Pocket PC h5400 Series to connect with a dual (802.11b & 802.11g) WLAN Access Point using the 802.11b technology. This Customer Advisory will be updated when the firmware is available for download as a SoftPaq.