1. Set Service type to Virtual user and Call property to Automatic switchboard. Configure Trunk access yes or no based on the actual requirements.
2. When configuring the AT0 trunk, the default called number is set to the access code of the automatic switchboard configured in the preceding step.
The U1900 cannot be connected to the SIP trunk though the public network because this involves the network address translation (NAT) issue. It is not allowed to use the SIP ALG function of the firewall because this function has not been tested under the lab environment. If the U1900 must be connected to the SIP trunk through the public network, use the session border controller (SBC).
No, because only one AT0 trunk line is available.
When the U1960 is configured with multiple AT0 trunks or the E1 digital trunk, multiple outgoing calls can be made in the conference to invite multiple participants.
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