HTC 10 User Manual page 187

HTC 10 dials as is and does not prepend your home country code when you
call phone numbers that are not stored in HTC 10. 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.
Resetting the reference country to default
1. From the Home screen, tap
2. Tap Assisted Dialing > Reference Country.
3. Under Reference Country, tap the bar and select the country whose settings
you want to set to default values.
4. Tap > Set Default.
, and then tap Settings > Call.
, and then tap Settings > Call.
Phone calls 187