As for voice calling, it uses about 300 kB with the standard sound quality (set by default) and about 600 kB with the high sound quality.
Note: As for video calling, we recommend that you use Wi-Fi.
If you need our support, click here to contact us.
SkyPhone User Support
Business hours to reply to your message: Monday to Friday 10:00 AM to 5:00 PM (JST), except for national holidays