ZyXEL's NSA-2400 is more than a Windows client back-up system. It will also back-up your SQL/Exchange server. The device supports CIFS/SMB protocols. For remote access it also supports FTP and HTTP/S. It can back itself up to another NSA device or an attached USB drive.
The four internal bays support SATA II drives up to 750GB. It supports RAID levels 0, 1, 5 and JBOD. In RAID 5 you can set it up for 3 drives plus a hot spare for maximum uptime should a drive happen to fail.
The array is powered by a 1.3GHz C3 CPU. There is 128MB of memory to boost transaction speed and allow concurrent sessions. It is all managed by a Linux operating system so more of the processor's power can be dedicated to keeping your back-up's up to date.