rsync with NAS540 over CLI

Hi Everybory,

I have different NAS and I have the Zyxel NAS542 for backup purposes only.

I saw there is a backup-app that configure from the 540 to others, but not in the opposite way

I would prfer to do it over CLI because I can configure it in diffenent server.

I used SSH to get in the nas, but there is no rsync command there:
# find / -name "rsync"
#

Any clue where I can download it? or how can I configure?

As workaround I'm mounting both NAS over NFS in a Linux PC and then doing there the rsync, but It's a waste of bandwidth.  

Thanks in advance.

#NAS_March