They will not know you are on FaceTime, and no messages will be sent unless you explicitly send one yourself.
When you receive a phone call during a FaceTime you are prompted to End FaceTime and answer the call or Ignor the call. Can you receive FaceTime calls while on the phone? On a FaceTime video call the video will get blocked and if you have opened his/her iMessage chat window the 3 dots may be present. Originally Answered: How can you tell if someone is on a FaceTime call while messaging me at the same time? On FaceTime audio you won’t be able to tell. How can you tell if someone is Facetiming someone else? Longest FaceTime Chat Alexis and Caitlin chatted on FaceTime for 88 hours, 53 minutes, 20.00 seconds. Simply restart your device to fix this problem. Some users have reported that they are unable to view recent phone calls (calls they have received or made) and/or missed calls because their devices are not showing their recent call history. Why is my iPhone only showing recent FaceTime calls? How do I get rid of pop up messages on my phone?.Why does a message keep popping up on my iPhone?.How do I turn off FaceTime and iMessage on my iPhone?.How do I stop Imessages from popping up on my iPhone?.How do I stop FaceTime from popping up on my iPhone?.Can you turn off FaceTime for one person?.Why does my phone disconnect from WIFI during FaceTime?.Why does my phone switch to data on FaceTime?.Do FaceTime calls show up on Sprint phone bill?.Do FaceTime calls show up on your bill?.Can you receive FaceTime calls while on the phone?.How can you tell if someone is Facetiming someone else?.What is the longest FaceTime call 2020?.Why is my iPhone only showing recent FaceTime calls?.