OK Lets see if we can get this working.
I did also find this port forwarding tester here...
But lets start at the beginning.... Step 1, Set your Omni to have a fixed IP address and use port 4369. Go to your keypad, and press SETUP (#9), then MISC (#6)
1) Press the down arrow, and you should see your IP address AND the port. Write Those Down.
2) Now, as you say, the OMNI doesn't use DHCP, but your router likely DOES, because of this you should reserve the OMNI IP address in the router, so your router doesn't give the address to anybody else. To do this you need the MAC address of the OMNI. There are several home port scanners out there that can find this. I use LANScan on the Mac, but there are free utilities on the PC too. Run a scan of your home network, and get the MAC address of your OMNI, at the IP address you found above. (Your router may tell you the MAC address as well.) Your MAC address might look something like this:
00:07:A6:01:21:47 Write this MAC address down.
3) Next step, reserve the IP in your router for this MAC address. On your NETGEAR Router... Select ADVANCED > Setup > LAN Setup
You should see "Address Reservation" and select ADD.
It will ask you for two things, the IP address, and the MAC address. You have them both. Save this, then reboot your router.
YES, your OMNI IP is fixed, but the router doesn't know that and MAY give this address to so other device. So this is a very good idea.
4) NOW we will open the port on the Netgear router. Port Forwarding....
Select Port Forwarding NOT Port Triggering. Select "Add Custom Service"
So you have to enter a "Service Name" and you can say "HAI"
Enter the IP address, and 4369 for both start port and end port, and pick "TCP/UDP" for protocol.
5) Now do you have DDNS? This is basically your public IP address. This MAY change, so you just can't write it down, as it will change. For now just Google "what is my ip address?"
6) Now click the link above, enter your public IP address, and port 4369, and does it say its open?
Hopefully, but its possible it may not, but lets assume it says its open.
Now back to DDNS, if you don't have that, you need it. I like DynDNS, that used to be free. I would find a free one. NOIP is free, but you have to login ever 30 days or they delete it. How these work, you register, and pick a name, then you run software on your PC/Mac to phones home and tells them your IP address. Maybe something like abc "123abc.DynDNS.com"
Then use 123abc.DynDNS.com in Snaplink as your IP address, use port 4369 as your port, and you should be set.
Hope this helps.