AltiGen comm 720 - Manual (Page 40)

32 IP 720 User Manual
Dialing an IP Number Directly from the IP 720
To dial an IP number directly from the IP 720 phone set, enter the IP
address, using the * key to enter periods and followed by the # key.
Note: This works only when the IP 720 is operating in Basic mode.
If the IP 720 is configured for a public IP address, you can call other public
IP address devices. If the IP 720 is configured for a private IP address, you
can call other private IP address devices that you can “see” or that are on
your subnet.