Little bit research on how to use Handoff feature on OSX Yosemite:
In order to use Handoff Feature from OSX Yosemite:
1. On Mac, go to System Preferences -> General, and check the box “Allow Handoff between this Mac and your iCloud devices”
2. On your iCloud devices (iphone), go to settings -> general -> Handoff & Suggested Apps, and Enable Handoff
3. On Mac, open Facetime and go to preferences. Check the “Allow iphone calls” box
4. Make sure bluetooth and Wifi turned on (both Mac and iphone)
5. Mac and iphone must be logged in with same iCloud account.
6. Must be on same Wifi network.
P.S. Look like that you need to check if your Mac support that by checking at System Report, and under Bluetooth Category LMP version needs to be 0x6. If anything lower than that, most likely handoff feature will not work.
