Two Types of Phone Calls
Your smartphone has two ways to make calls: the regular Phone app (using cellular network) and LINE calls (using internet). Each has strengths and weaknesses.
Regular Phone Calls
Uses the cellular network. Stable audio quality, can call emergency numbers (110/119), works with any phone number including landlines. Costs money unless you have an unlimited plan.
LINE Calls
Uses internet (Wi-Fi or mobile data). Free, supports video and group calls. But can't call emergency numbers, requires both parties to have LINE, and quality depends on internet connection.
Data Usage
LINE voice calls use about 0.3 MB/minute (18 MB/hour). Video calls use about 5 MB/minute (300 MB/hour). Voice calls barely affect your data plan; use Wi-Fi for long video calls.
When to Use Each
Regular phone: emergencies, businesses, people without LINE, important calls. LINE: chatting with friends, group calls, video calls, international calls.