VoIP phone is a SIP phone or phone program. It allows users to call any telephony program, mobile phone or landline using IP (VoIP). Thus, the sound is carried over the internet instead of the traditional PSTN system. It can also be a VoIP phone, a simple software-based telephony program or a hardware tool such as a regular phone. Some common VoIP phone features are: Caller ID, park the call, transfer the call, and hold the call.
DID-Direct Internal Call (also known as DDI in Europe) is a feature that phone companies offer to their subscribers. This feature is used with PBX systems owned by subscribers. Telephone companies assign their customers a number field associated with one or more telephone lines through the DID system. The purpose of this is to enable a company to give special phone numbers to all employees without allocating a separate phone line to each employee. In this way, telephone traffic can be divided and managed more easily. To take advantage of the DID feature, you must purchase an ISDN or digital line and ask the telephone company to assign you a number field. You will then need DID compatible BRI, E1 or T1 cards or gateway equipment for use in your own business.
RTP - An abbreviation for Real Time Transport Protocol; Refers to the standard packet format used for transmitting audio and video over the Internet. RTP is defined in RFC 1889. This protocol was developed by the Audio Video Transmission group of employees and was first introduced to the general public in 1996. RTP and RTCP are highly interconnected; the data itself is transmitted by RTP, and RTCP is used to provide feedback on the quality of this service.