The Avaya IP Softphone is an IP telephone client for Windows-based PCs .
IP Softphone 2050 transforms your PC into a full-featured platform.
Provides you everything you need to facilitate communication around the office.
Avaya one‐X Communicator is a rich Unified Communications client.
A small application that allows you to make and receive calls with Callcentric.
It enables you to make voice and video phone calls using SIP-based standards.
Mizu Softphone is a professional VoIP softphone for Windows users.
Provides professional technology for VoIP voice calling.
A basic SIP Softphone that allows to connect to VoIP PBX and providers.
A free SIP Softphone which offers PC-to-Phone service.
A sip softphone for making and receiving VoIP calls.
PortSIP Solutions, Inc.
PortGo is the newest SIP softphone from PortSIP, it's built base on PortSIP VoIP.
IntuitTech Sdn. Bhd
hayibo is the first SIP softphone application written for business users.
sipLite softphone is a free softphone which works with SIP protocol.
The new AGEphone Desktop 2 is SIP based internet telephony softphone.
PortSIP Sutions, Inc.
Softphone compatible with SIP for voice over IP PBX or international providers.
Ecotronics Ventures LLC
Kapanga Softphone is a powerful and unique SIP software telephone.
"VidPhone" is a H.323/SIP Video SoftPhone for Windows and Linux OS.