I am trying to connect three 7400's over a private WAN.

I can DM each system from each other but when I try to call a group via SPnet the system grabs a MGI channel and a SPnet trunk but I get a 'No user response'.
I have a call accounting system connected to SMDR that is sent off-site so I do not have access to that. Is there any other way to monitor what is happening?

On each system, using the DM tool, in 5.2.8 put in the IP address of the other 2 systems MP40. As the systems are probably in different subnets, it sends everything to the public IP - including MGI traffic.

No user response means the mp40 card's can't talk to each other.
Check the ip is correct in the network table.

What VIBob says is only true if you have private with public enabled for the MP and/or MGI (OAS) cards.

I have private with public as we will also have IP phones outside the private WAN. So I had setup the link IDs MMC820 with the public IP. Changed to private and added MMC838.
Work good now. Now I am trying to figure out if they want ext to Ext across three sites is it possible with 3 digits.

Thank you both for your help.

I have a setup that had the link working between two sites, and we had to go to 4 digit extensions, but that was because they were all over the place with the extension numbers, made if all 2xx and then 3xx no problem we route the intercom via the first digit.

What are you using for the WAN? VPN and if so which equipment. Setting the VPN has been nothing but a headache. Thanks for any help.

These sites are using a metro-Ethernet inter-connect using private IP addressing. VPN should give you the appearance that you are on the same network as the remote.