UC, Lync 2013, Call a Contact on Their Work or Mobile Number with Lync 2013 for iPhone
On this page, you can learn how to make a phone call using a contact's work or mobile phone number on Lync 2013 for iPhone.
To call someone on their work or mobile number, tap Contacts, find the person in your Contacts list, or type the person’s name in the search box. When you find the contact, tap their name, and then either their work or mobile number. This will call the person on their work line or mobile phone.
Depending on how you set your VoIP call options, when you make a call it could use Wi-Fi or your cellular data plan. For more information, see Manage Wi-Fi for VoIP options.