For wireless access you can decide whether to let 802.11b and g clients mix it up or only allow either type. You won't find any useful help about the Mixed_Long wireless setting but you probably won't need to use it anyway. This is provided in case you're having trouble getting legacy wireless clients to connect. All it does is tell the access point to send a mixture of short and long preambles which is the data in each packet header that has information about the wireless network.
Wireless security is present and correct with WEP and WPA/WPA2 on the menu along with SSID masking. Wireless MAC address filters can be applied and you can use either white or black lists depending on whether you want to block or only allow access to those systems listed. The WDS (wireless distribution system) feature allows you to add up to four other access points acting as repeaters to create a completely wireless network. The router also supports 802.1x although we can't see typical users of this product requiring external authentication via a RADIUS server.
With only 802.11g on the case wireless performance won't be spectacular but Zoom delivers speeds that are on a par with most competing products. For testing we used a Zoom Wireless-G USB adapter in a notebook running Windows XP SP2. At a mere £17 the adapter looks good value and the installation routine loads a handy status utility that helps locate wireless networks and connect to them.
Copying a 690MB video clip over a close range WPA2 encrypted link returned an average speed of 25Mbps. With the notebook located on the floor below the router we saw a drop in signal strength of around 50 per cent with copy speeds falling to around 15Mbps.
For general Internet security the base SPI firewall can be beefed up using the advanced settings where you add your own security policies comprising custom rules. Usefully, separate policies can be applied to the WAN, LAN and DMZ systems. A single DMZ (demilitarised zone) entry allows one LAN system to step away from the firewall and share the public IP address whilst virtual servers can be added to route inbound traffic to specific servers based on port ranges.
If you're strapped for cash and need a low cost broadband router with integral ADSL modem and basic wireless access point then the Zoom ADSL X6 5590 is worth considering. We found it very easy to set up with a surprisingly good range of security features and although wireless performance is pedestrian it is good enough for casual web browsing and email.