Softphone

A softphone is a phone that lives in software. Instead of a physical handset on the desk, the agent gets an app on a computer or mobile device that does everything a phone does — dial, answer, mute, hold, and hang up — but carries the audio over the internet. It plugs into a headset and behaves like a regular phone from the agent's point of view.

Under the hood a softphone speaks SIP (Session Initiation Protocol) to register with the phone system and uses VoIP to carry the call audio. Registration is the step where the app proves who it is and tells the server where to send calls; if Phone registration fails, the softphone simply will not ring. Most setup problems with a new agent trace back to that single handshake.

It helps to place the softphone among its cousins. A Webphone is a softphone that runs inside a browser tab, so there is nothing to install. A Hardphone (deskphone) is the opposite — a real desk handset with its own hardware. A standalone softphone app sits in the middle: more capable than a quick browser tab, less fuss than buying and shipping deskphones. For most VICIdial floors the browser-based webphone has become the default, but knowing the softphone family helps when you need a fallback or a more featured client.