HTC One M9 User Manual page 179

3. If there are a number of matches found (for example, 8 matches), tap the
number to see all the matches.
4. Tap the contact you want to call.
If you selected a contact whose phone number has a leading zero,
HTC One M9 will automatically prepend it with your home country code when
dialing. If there's already a plus (+) sign and country code before the phone
number, HTC One M9 will just dial as is.
HTC One M9 dials as is and does not prepend your home country code when
you call phone numbers that are not stored in HTC One M9. When manually
entering a phone number to call, you need to enter a plus (+) sign and country
code before the number.
Editing a country's international call settings
1. From the Home screen, tap
2. Tap Assisted Dialing > Reference Country.
3. Under Reference Country, select the country whose settings you want to edit.
4. Tap > Edit.
5. Edit the Country Code, IDD Prefix (International Direct Dial), NDD Prefix
(National Direct Dial), Area/City Code and National Number Length (length
of phone number).
6. Tap Save.
7. Tap Done.
, and then tap Settings > Call.
Phone calls 179