In iPhone, go to Settings, tap on Sounds, then toggle, "Vibrate on ring"
You also want to make sure your alert sound is turned up. The volume up and volume down is set up so it controls alert volume at factory default. To disable changing the alert volume with the up and down volume switch, go to Settings, sounds, toggle off "Change with buttons"
Tell me if this helps you.
Hi Joe, thanks for your comment.
Those recommended settings are actually configured in my iPhone5. The symptom of my problem are:
- If the incoming call has caller number display, the iPhone5 will display the caller number, and can ring => no problem.
- If the incoming call has caller number blocked, the iPhone5 will display "Blocked", and the phone can ring => no problem.
- But if the incoming call has no caller number (e.g. sometimes caller from overseas call using Skype phone to call), the iPhone5 will display "Unknown"; in this case (whenever the incoming call is displayed as "Unknown"), then the iPhone5 will not ring. => Problem. I can still answer the call with conversation if I see there is incoming call on the iPhone5; if I don't see it, I will just have miss call then because there is no ringing alert.
The reason I think it doesn't ring is because the caller isn't calling with an actual phone number or FaceTime email. That's what I think, but I could be wrong. Since the iPhone is an actual phone, it's not going to recognize anything other than a phone number or FaceTime email. Skype is different though, I'm not sure if Skype uses phone numbers or email for calls. Hope this helps.
Have you had this issue solved - as i also have this problem, had been waiting for confirmation on a delivery of a fridge/freezer and each time i checked my phone i had these missed calls from 'unknown'. Luckily i was able to answer a call showing unknown as i had just picked it up and noticed the incoming call. Very annoying - could have missed the delivery!
I'm having this problem as well on my iphone 4S. If the caller is "unknown" it does not ring or vibrate but if I happen to be looking at the phone I will see the call and can answer it. All other incoming calls ring or vibrate normally.
This problem just started happening out of the blue - it used to ring when I recieved called from "unknown".
Are there any solutions out there for this?