ZyXel ZyAir AG-225H Wi-Fi sniffer
Using the AG-225H as a USB wireless adapter is simple enough: you install the drivers and configuration utility first and then plug in the device. The utility is accessed from the System Tray and its icon changes colour to denote the connection status of the adapter. The Network screen provides plenty of information about the current wireless connection and shows the AP's SSID, whether Infrastructure or Ad Hoc modes are in use, the signal strength and general network IP settings. Profiles are used to manage different AP connections and these can be easily created from the utility to include an SSID and security mode. Usefully, the utility can run a full site-survey, which displays all discovered APs allowing one to be selected for use in the profile. Wireless security features are extremely good, with support for 64/128/256-bit WEP plus WPA and the latest WPA 2.
To use the adapter as an access point you need to have it connected to a system with the ZyXel utility installed and linked to the LAN via a wired connection. To swap modes you simply select one from the drop-down menu in the utility interface and it is automatically applied to the adapter. However, there is more to do as the LAN and WLAN connections on the system being used for AP duties must be bridged. Typically, ZyXel points out in its manual that this needs to be done and then forgets that some instructions and an example might be rather useful. It's actually fairly simple as you open the Windows Network Connections from the Control Panel, and select the LAN and WLAN icons together with the Ctrl key held down. From the Advanced menu select Bridge Connections and a bridge will be automatically created. We found a bridge connection worked fine allowing our wireless test clients to access the internal DHCP server and other resources on the LAN via the AG-225H. Security features are reasonable as you can implement 64/128/256-bit WEP encryption (but not WPA) and enable a MAC address control list.
The ZyAir AG-225H could prove to be a really handy gadget for mobile users. The access point mode does have some limitations but it certainly impresses as a wireless hotspot locator and USB adapter and comes at a price that's less than some standard USB wireless adapters.