Returning A Missed Call; Using Speed Dial - HTC One User Manual

Returning a missed call

You'll see the missed call icon
1. Slide the Notifications panel open to check who the caller is.
2. To return the call, spread your two fingers on the missed call
notification to expand it, and then tap Call back.
If you have multiple missed calls, tap the missed calls notification to open
the Call History tab.

Using Speed dial

Use Speed dial to call a phone number with a single tap. For example, if
you assign a contact's number to the number 2 key, you can just press and
hold 2 to dial the number.
The number 1 key is reserved for your voicemail. Press and hold
this key to call voicemail and retrieve your voicemail messages.
Assigning a speed dial key
1. Open the Phone app.
2. Tap > Speed dial >
You can also press and hold an unassigned key on the dialpad, and
then tap Yes.
in the status bar when you miss a call.
.
Phone calls 105