For security, the router supports all existing wireless-encryption methods including WEP, WPA, and WPA2. As mentioned earlier, it also comes with Wi-Fi Protected Setup features that allow you to add a new client to the network at the press of a button, instead of having to type in the encryption key manually.
We tested the Zyxel X-550NH with a Linksys WUSB600N wireless adapter and the router performed terribly when it came to data transferring, both with the stock antennas and with the high-gain antennas.
In the Throughput test, where we test a router at its best settings with a wireless client that's only 15 feet away, the X-550NH scored 16Mbps, compared with the X-550N's 50.2Mbps. At this speed, the router would take more than 4 minutes to finish transmitting 500MB of data.
Performance didn't improve in the Range test, where the client is 100 feet away from the test router. In this test, the X-550NH registered only 7.2Mbps. In the Mixed mode test, where the router was set to work with both Wireless-N and legacy wireless-G and B clients, it scored merely 9.6Mbps.
These scores were by far the slowest we've seen in a wireless router. We suspected that the router came with some faulty firmware, but the Zyxel's support site doesn't offer any firmware updates, even though it did for the X-550N.
The router also failed our 24-hour stress test. In this test we transfer a large amount of data back and forth from different wireless clients to see if the test router can hold the connections continuously over an extended amount of time. The Zyxel X-550NH's signal reset after a very short time, and continued to do this every a few hours. We also lost the connection to the Internet from the wireless client at times, even when the local connection was live.
Despite the extremely long range--more than 340 feet away with the use of the high-gain antennas--we couldn't see how the X-550NH is useful as a viable wireless networking solution. Hopefully a firmware update can fix this.
(Longer bars indicate better performance)
Service and support
The Zyxel X-550NH comes with a two-year warranty, which is better than the one-year warranty that most routers come with. The support page on Zyxel's site offers nothing for the router except for a PDF of the router's spec sheet; there's no sign that there will be firmware update in the future. The company's toll-free technical support is available Monday through Friday from 7 a.m. till 7 p.m. PT, and Saturday and Sunday from 8 a.m. till 2 p.m.