handset icon with arrow point right and up left of contact name on recent calls list, what is that icon?

Never thought I saw this icon till iOS 7 but I guess its also in iOS 6 just underneath the name of the conact in your recent calls list. Now its to the left of the contact name in recent calls list and I'm just wondering what icon is this? Some of my recent calls have this icon and some dont.

Thanks in advance!