1. ATA This term means analog telephone generator and its the device used to connect the standard phone in your home to digital data so it can be transmitted over the Internet. ATA is also referred to as an analog-to-digital converter. The analog signal from your phone is simply converted into digital data that will be transmitted on the Internet.
2. H.323 this term defines the protocols used to provide audio-visual communication sessions on any packet network. H.323 is a system specification used to describe ITU Telecommunication Standardization Sector (ITU-T). The standard uses various codecs, that includes: video codecs (H.261, H.263, H.264), audio codecs (G.711, G.729, G.729a, G.723.1, G.726) and text codecs (T.140).
3. MGCP The Media Gateway Control Protocol is another protocol used in the VoIP system. Also known as H.248 and Megaco, the MGCP deals with signaling and session management during a conference. This protocol is the result of combining other two protocols the Internet Protocol Device Control (IPDC) and Simple Gateway Control Protocol (SGCP),
4. SIP - The Session Initiation Protocol is a standard for multimedia conferencing over IP. SIP is designed to manage sessions within a packet telephony network. SIP also deals with signaling, that allows information to be carried over the network.
5. Megaco - Megaco/H.248, the Media Gateway Control Protocol, is used between a Media Gateway and a Media Gateway Controller in a VoIP network.
