Description: SIP Phone DLL allows to make PC-PC, PC-phone, or phone-phone calls or create Instant Messaging (IM) sessions over the Internet VOIP SIP Phone SDK brings protocol support for ActiveX. With this SDK one can create a simple program to connect and start speaking with anyone with a direct IP Address (provided no NAT Router or Firewall is set) or use the Gateway or the Gatekeeper to connect to /or from PSTN lines.