Computer telephony software; computer server software for controlling, managing and establishing connections among client applications and between client applications and telephone networks; softphone software; computer software for providing voice and video communications to and from remote users on computers and mobile devices via a global computer network, local area networks (LAN), wide area networks (WAN), public switched telephone networks (PSTN), and mobile telephone networks; computer software that enables enhanced telephone activities such as voicemail, auto attendant, multi-party conferencing, instant messaging, presence, presence management, call forwarding, call transfer, call logs, directory services, speed dial, voicemail forwarding by email, contact management, video chat, and other features and activities to be accessed and performed via computers and mobile devices; computer software for the transmission of sound, voice and video communications via IP global computer networks; computer telephony integration (CTI) software to enable computers to act as call centers; computer software that allows users to utilize private branch exchange (PBX) networks and voice over Internet protocol (VOIP) technology remotely; Software Development Kit (SDK) software that allows the development of the aforementioned; user manuals and instruction books in electronic form distributed