About the local regeneration call source of U1900 series unified gateways, which of the following statements are CORRECT? (Multiple Choice)
A . The purpose of configuring the local regeneration call source is to implement the local regeneration function for local SIP users.
B . The purpose of configuring the local regeneration call source is to implement the local regeneration function for local POTS users.
C . The local regeneration call source is configured on the primary node.
D . If the local node has only SIP users, the local regeneration call source is not required.
Answer: BD