Cisco UC320W Configuration Manual page 52

In the example system used for testing UC320W for Cbeyond, 3 DIDs are assigned to
a test account that was applied to the test unit.
The first DID, shown in the screenshot below, is 678-397-2544. This is the "main
number" that is used to authenticate the SIP trunk and in this example remains
assigned to the AA for general inbound calls. Note that the Routing Group Label has
been changed to Main Number. This is for clear identification of the mapping
between the Main Number DID to the AA number, in anticipation of moving the
other DIDs to new route groups.
Clicking the Move button next to the number 678-397-2545 in the test UC320W
creates a new Routing Group, as shown in the following screen shot. In this
example, the new Routing Group Label is changed to "John Smith" to show than the
routing for this DID 678-397-2545 is applied to John Smith's telephone extension
101, as defined in a previous Wizard step. "John Smith (101)" is selected for the DID
from the drop down on the right of the screen.