1. Telephony is the transmission of voice, data, video or image signals. It has most commonly been used to refer to the integration of the telephone with the PC or other device. Internet telephony enables people to use the Internet as the transmission medium for telephone calls. Even though Internet telephony doesn\'t offer the same quality as conventional telephone services, it enables users to make free telephone calls anywhere in the world. Internet telephony products are sometimes called IP telephony, Voice over the Internet (VOI) or Voice over IP (VOIP) products.