Voice over IP (VoIP)
VoIP is the technology that carries phone call audio as data packets over Internet Protocol (IP) networks instead of traditional telephone circuits.
Voice over Internet Protocol (VoIP) turns speech into digital data packets and carries them over IP networks. Cloud phone systems, SIP lines, browser-based calling and AI voice agents are all built on it. For the caller the difference is usually invisible: the other end may be an ordinary landline or mobile phone, and part of the call still travels over the internet.
How it works
A VoIP call involves two separate jobs. Signalling, which sets up, routes and ends the call, is usually handled by SIP. The audio itself travels in RTP (Real-time Transport Protocol) packets: a codec compresses the voice, and the receiving side turns the packets back into sound. When a call goes to or comes from the traditional phone network (PSTN), a carrier gateway translates between the two worlds.
Why it matters
VoIP frees the phone from a physical line and an office: staff can take calls on the same number wherever they are, and software can route, record and transcribe every call. Call quality depends on the network, though. Packet loss and jitter can break up the audio, so a sufficient and stable internet connection matters.
In Speakline
In Speakline, calls arrive from your carrier over SIP, and your operators talk from the browser without installing anything, thanks to WebRTC. The AI voice agent joins the same audio stream. See Call center for details.