Cisco VOIP Phones
What is VOIP?
VOIP is short for Voice over Internet Protocol. Voice over Internet Protocol is a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions of the PSTN (Public Switched Telephone Network). -http://www.webopedia.com/TERM/V/VoIP.html