[cisco-voip] a router for transcoding

[James Grace]

we have a central site and 4 remote sites.  we only have cm servers and unity server at the central site.  we put a router at the central site for transding overflow if needed.  my question is why would we need a router for transcoding overflow.  Someone told me that it would be for conference calls on the system.  can someone help me understand this.  our unity server is set for g729 
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