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In the Passthrough Outgoing Call Rule collector box, highlight the Internal rule, and click Allow. This allows extension to extension dialing. Note: if there is a need to share other outgoing rules, this is where you would allow access to those rules.
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In the Caller ID Settings tab, set Support Changing Caller ID to 'Yes'
Under the Connection Settings tab, set Qualify Hosts to 'Yes'. When this option is enabled, SIP option packets are sent every 60 seconds- this helps keep NAT tunnels open. In addition, latency responses are shown on the system status page.
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In the Call Settings tab, set G722 to 'ON' when using Digium phones (the remainder of the settings may be left to their default settings).
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