I looked at the 518-215-407 BSP. That's what raised some of the above questions. I have not looked at the xxx-400 BSP in its entirety but I did not see anything about a 403 KTU even when I Googled it so thanks for explaining that to me.
I have a couple follow-up questions:
1. Do you just insert a Music-on-hold card in one of the line card slots and you get MOH? Say you inserted it in line 4's slot: do you get MOH on the other three lines if you push the Hold button, or do you push line 4 to get MOH?
2. BSP xxxxx-407 says a maximum of 5 stations can be wired directly to KSU (and I understand that.) "If more are required, use loop through terminations or provide destribution facilities." That I don't understand. Is the connector block in the KSU a different type than that a normal 66? It appears to me in my limited knowledge that the connector block in the KSU is a special 66 block. Is that true?

Bill