Lync Online and Lync Server both support connectivity with Skype. This connectivity allows Lync and Skype users to communicate with each other, add each other as contacts, and see each others’ presence. This guide for Lync Online administrators and Lync Server Administrators describes how to enable connectivity between Lync and Skype users.
In order for Lync and Skype users to fully communicate with each other, the following requirements must be met:
Skype user must be logged into their Skype client with a Microsoft Account (MSA).
Lync users must be enabled for public IM connectivity by their Lync administrator.
When a Skype user adds a Lync contact, verify that below the contact’s name the word Lync appears. This indicates that a Lync URI was found.
When a Skype user adds a Lync contact and zero search results are returned for that Lync domain, the PIC provisioning process may not have completed or the Lync domain has not yet been set up.
Lastly, depending on the privacy settings of the Lync and Skype users, IM and presence may not work until contacts are accepted by each user.