VaxVoIP SIP Server SDK is a new, flexible approach that combines several advanced features, enabling users to create their own VoIP Server and IP PBX systems
VoIP SIP Client SDK - A powerful and highly versatile VoIP SDK. Our SIP SDK provides a powerful and highly versatile solution to add quickly SIP (Session Initiation Protocol) based dial and receive phone calls features in your software applications.
Free VOIP / SIP phone (softphone). Use your PC as a phone. Works with any SIP / VOIP provider and phone service. Easy to use interface to transfer, forward calls or review history of calls. Free download from http://www.3cx.com
Carousel is software to connect VoIP calls to ordinary telephone lines and vice versa using one of a number of professional telephony devices. It works as a virtual FXO gateway.
OfficeSIP Softphone is an audio / video softphone for Windows primarily for use in business scenarios, offering you an efficient and easy way of communication for free.
"Monitoring The Web" is a simple and convenient tool designed to help you increase your site's uptime and effectiveness. Supported protocols are HTTP, HTTPS, FTP, PING, SIP (VoIP). Warning e-mail notifications.
Free VOIP / SIP phone (softphone) for Windows. Use your PC as a phone. Works with popular VOIP providers and SIP PBX's (including 3CX Phone System). Easy to use & light weight. Full version, not a lite version! Free download from http://www.3cx.com