Trouble networking 5 BCMs

[Crowtalks]

I am installing 5 BCMs for a bank. The main is a BCM 400 3.7, the branches are BCM 50s. I have installed several BCMs but this is the first network. I am using 3 digit DNs to mirror the old systems.

I had a ticket open with ITAS on a different issue but mention the network I was struggling with and the ITAS Eng. told me that I couldn't network these 5 systems unless I went to 4 digit DNs.

Classwork and certification being a couple of years behind me, I am a little rusty on what we did in the classroom environment, but I could swear we networked the classroom systems using 3 digit DNs across VoIP trunks.

I have already found out that 5 of the single digit access codes are eaten up by the internal DNs, which is a pain.
How can I network the 5 systems using 3 digit DNs and CDP over VoIP trunks? Help, Jim

 

[Crowtalks]

I was trying to use 3 digit extentions to mirror what they have now, with each site having a different leading digit. That tied up 6 of my line pool access code digit for cdp over VoIP at the 400. I was trying to figure out a solution around this where the customer could still use CDP and dial the shortest amount of digits possible to the other 4 sites. I could use udp, but that's not a workable solution.
I dug out my notes from training (I'm lucky I found them) and we used 4 digit DNs there for private networking instead of 3 digits, revealing that my memory is quite faulty.
I have decided to go to 4 digit DNs to open up my pool codes and thus solve the problem.
I think I remember how to set up cdp, but I may be posting back for help on the process.
Thanks, Jim