Connect the ooma modem port to the cable/DSL modem. Connect your router WAN/Internet port to the Home port of ooma. Connect the Vonage adapter to a LAN port of your router. Configure the ooma DMZ to have the IP address of the router. Configure the router DMZ to have the IP address of the Vonage adapter.
Telo with 2 Handsets, a Linx, and a Safety Phone
Telo2 with 2 Handsets and a Linx
Cable connection (round 75 ohm cable tv connector) goes into into cable modem.
Ethernet/WAN port out of cable modem connects to WAN port on the Vonage box,
PC port on the Vonage box connects to the MODEM port on the Ooma Hub.
PHONE port on the Ooma hub is connected into my house telephone wiring.
HOME port on the Ooma hub is connected into my Linksys Router WAN port.
Linksys LAN ports connected to several PCs that I use.
In my case, all of this is physically located at the service entrance to my house in the basement. My Ooma hub, cable modem, and Vonage box are all physically next to each other at the service entrance. I rewired my home telephone wiring to put my Vonage number on the line 1 cable pair (this would be the red/green wires which is what a normal landline for a single phone number would use). My Ooma line is connected to the second wire pair (black/yellow). So, when my Vonage number rings it lights up line 1 on my 2-line phone. When my Ooma number rings, it lights up line 2 on my 2-line phone.
I don't currently use the Scout and once my Vonage number is ported over to Ooma, I will probably rewire my house to make use of the Scout. But for now, the above works for me.
Everything was pretty much plug and play with no special setup or IP configuration.
The only gotcha that I can think of is that you may need to power cycle everything (ie turn everything off then on, especially the cable modem). Adding or subtracting equipment from the network can cause problems with IP address assignment or MAC address recognition if you don't power cycle everything after making changes. When you power down, leave the power off for a minute or so before re-applying power.