Direct inward dialing

DID is a unique number, which we need to associate to a Lync user, every time we enable the Enterprise Voice option (as we can see in the following screenshot) or the conference features.

It is not a mandatory setting, but if a user does not have a DID number, he or she can only be reached through an internal extension.

Note

It is a best practice to also populate the Active Directory (AD) with phone numbers that are globally unique because Lync relies on the AD to provide a company-wide directory service.

The format of the Tel URI is dictated by the RFC 3966. The number used in the previous figure is a E.164 number, so we have the + sign, the Country Code, the City / Area Code, and the Local (User) Number. The result is a phone number that can be used to call the Lync user directly from a public/PSTN telephony system. The Ext parameter is a supported extension that we need for conferencing (for example, in dial-in conferencing to authenticate the user). To have a representation...