Clicking the handset icon in the business card of a contact in Microsoft Outlook 2016 does not trigger dialing to one of the stored phone numbers.
Example: Telephone receiver icon with an arrow for the selection list (initiate outgoing dialing)
To initiate dialing to a phone number by clicking the handset icon, the selection list must be expanded and the specific phone number must be explicitly selected.
Explanation of how it works in conjunction with Microsoft Outlook 2016
If you simply click on the handset icon, the stored contact data such as phone number and IM (instant messaging) address may not be correctly assigned to telephony or messaging.
If the handset icon is pressed in the Microsoft Outlook contact (without opening the selection list) and an Instant Messaging (IM) address is entered, this IM address is transmitted to the ProCall Client for Windows and thus a connection attempt is made via AudioChat/Chat.
Also when pressing the speech bubblein the contact card, Microsoft Outlook sends the entered instant messaging (IM) address to the ProCall Client for Windows.
The described behavior may differ if the Microsoft Outlook version is different. The description of the behavior is based on observation since we do not have specifications on how Microsoft Outlook works.