What does "Sync Android Contacts" in v1.9.4 do?

[Miguel]

I need to sync one-way from DJO to Android to keep the dialer happy but am afraid of syncing in the other direction for fear of loosing data.
What does this button do? In the forum the answers don't seem clear to me.
Miguel

[tenholde]

I, too, am confused about contact sync with android people app. I need to sync DJO and outlook 2-way, and have whatever is in DJO copied to the android People app (because that is the only way to use DJO contact info in the dialer??)

[DJOCTO]

The sync is always two ways.