Ohjelmistopuhelin

Ohjelmistopuhelin, literally “software phone,” is a communication device that operates entirely through software rather than dedicated hardware components common to traditional telephone handsets. The device typically runs on a computing platform such as a desktop computer, laptop, tablet, or mobile phone, and uses the device’s existing audio input and output hardware (mic, speakers, headphones, or Bluetooth accessories) to connect with Voice over Internet Protocol (VoIP) networks. By integrating with a VoIP protocol stack—most commonly SIP for call signaling and RTP for media streams—an ohjelmistopuhelin can place, receive, and manage calls over the internet just as a conventional telephone would over a PSTN line.

The concept dates back to the early 1990s with the rise of Internet telephony applications, but the term became especially popular in Finland after the launch of the first nationwide VoIP infrastructure. Finnish telecom operators encouraged the use of software phones through subsidized licenses and compatibility with their access network. Modern implementations often combine standard telephony features with multimedia capabilities such as HD audio, video, instant messaging, and call routing. Many commercial products, such as Polycom ExpressConnect and various open‑source platforms (Asterisk, 3CX), provide software phone clients that can be deployed on Windows, macOS, Linux, and Android.

Programmatic APIs allow developers to embed voice call functions inside other applications, enabling advanced use cases like customer‑support portals, telehealth services, and integrated communication suites. Because an ohjelmistopuhelin relies on existing network infrastructure and general‑purpose computing hardware, it eliminates the need for separate handset manufacturing, reduces deployment costs, and offers greater flexibility for remote or distributed work environments. The continued growth of broadband and 5G connectivity suggests further expansion of software‑based voice services in both consumer and business markets.