Aastra AastraLink Pro 160 Administrator's Manual page 53

Configuring Aastra IP Phone Accounts
Managing IP Phone Users
• SIP DID Number
Specifies the SIP Direct Inward Dialing (DID) number to this IP phone. A
DID number is an individual telephone number assigned to this phone that
allows an outside caller to dial directly from incoming SIP trunk calls to the
users extension, without having to route via the Operator or IVR menu
system.
41-001190-02 Rev. 01, Rel. 1.2 3-9