1. On the remote unit, you need to add a route to tell it how to access IP addresses that are not its local network. Most commonly you will do this by adding a default route. From a telnet or terminal session use the following command:
   
   add route default x.x.x.x net 1
   
   (where x.x.x.x is the address of your router, in many cases x.x.x.1).  You can test this route by pinging from the Systech Device Server to the host that wants to access the Systech Device Server and vice versa. 
2. Note that for the above to work, your host will also need a default route to get back to the Systech Device Server. In many cases, especially if you have internet access or WAN access already setup, this route will already be set. But if not, then go to the Network control panel and add a default route to the TCP settings.
3. In the NativeCOM control panel, when you add a port or port server, instead of choosing a unit from the list, you will need to click the button "Add Unlisted Port Server". In the resulting dialog, enter the IP address of your remote Systech Device Server and click OK.

Note: There could be a bug in the browser interface such that makes it so that when you add a route with the browser, it is not added to the current route table. You must save and reboot.