Matrix: Are the CCI-22 rear panel DB-9 connectors wired in parallel?

Question:  Do I have to use both DB-9 connectors on the CCI-22 interface rear panel card when using a two channel Clear-Com wired PL system wired into the CCI-22 card? 
Answer:  The DB-9 connectors on the CCI-22 rear card are wired in parallel, so only wiring up one DB-9 is necessary when connecting two channels of Clear-Com party-line into the CCI-22 card.  See the drawing below: 

It is also ok to use both DB-9 connectors to wire up a two channel Clear-Com system, that is one DB-9 is used to support channel A and one DB-9 is used to support channel B.  In this case the wiring of the two channels using both DB-9 is shown below:

The advantage of using both DB-9 connectors is redundancy, using this scheme allows for channel B to function if there was a fault with the channel A wiring, both the channel B audio and DC PL power would still be present at the CCI-22 card.


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