How calls travel
VoIP, Wi-Fi calling, codecs and call quality, explained without jargon.
- How much data does a VoIP call use? The calculation, codec by codec
Work out how many megabytes an internet voice call uses per hour: codec bitrate, packet headers, both directions, and why video calls are a different story.
- Satellite texting on an ordinary phone: how direct-to-cell works and what it can do
How a normal smartphone can reach a satellite when there is no mast in range, why texts come before calls, what the FCC's 2024 Supplemental Coverage from Space rules require for 911, and what to check before relying on it.
- VoLTE and the 2G/3G switch-off: will your phone still make calls?
What VoLTE is, why operators are switching off 2G and 3G networks, which phones are affected, and how to check whether your phone, or a relative's, will keep working.
- What is VoIP? How a phone call travels over the internet
VoIP explained step by step: signalling with SIP, voice packets with RTP, codecs, NAT traversal and the difference between app-to-app calls and calls to real phone numbers.
- Why VoIP calls break up: latency, jitter, packet loss and how to fix them
A practical troubleshooting guide for robotic voices, echoes, one-way audio and dropped internet calls, from Wi-Fi placement to router settings.
- Wi-Fi calling explained: how it works and how it differs from calling apps
What carrier Wi-Fi calling (VoWiFi) is, how your phone reaches the operator over any Wi-Fi network, what it costs at home and abroad, and when an app call is the better choice.
