MicroSIP – lightweight VoIP SIP softphone for Windows – Official Homepage

MicroSIP – open source portable SIP softphone based on PJSIP stack
for Windows OS.

It allowing to do high quality VoIP calls (person-to-person or on
regular telephones) via open SIP protocol. From cloud of SIP providers
you can choose best for you, register account and use it with MicroSIP.
You’ll get free person-to-person calls and cheap international calls.

Main in MicroSIP:

• small footprint (>2.5MB) and RAM usage (>5MB) – written in C
  and C++ with minimal possible system resources usage
• usability – user friendly in daily usage
• functionality – voice; video H.264 and H.263+, VP8; SIMPLE messaging
  (RFC 3428) and presence (RFC 3903, 6665); DTMF In-band, RCF2833, SIP-INFO.
• compatibility – conform to SIP standards
• voice quality – supports best voice codecs: Opus, G.711 A-law and μ-law, G.722, G.721.1, G.723, G.729, GSM, AMR, AMR-WB, iLBC,
  Speex, SILK and Linear PCM mono/stereo.
• WebRTC echo cancellation algorithm and voice activity detection
• privacy – configurable encryption TLS / SRTP for control and media
• portability – has no additional dependencies and stores setting in
  ini file
• multilanguage and RTL support, localization for bulgarian, chinese,
  dutch, estonian, finnish, french, german, hebrew, hungarian, italian,
  korean, norwegian, polish, portuguese, russian (микросип), spanish, swedish,
  ukrainian, …
• can be used by people with visual impairments using screen reader software such as NVDA

Enjoy!