Patent ID: 9456388
Filing Date: 2016-09-27
CPC Classification: H04L,H04W

Claim Text:
1. A communication system, comprising: a network node; a first terminal which supports a first codec; and a second terminal, wherein the first codec supports a codec A compatible mode and a codec A non-compatible mode, the first codec being a new codec and codec A having a dedicated payload format, the codec A compatible mode is compatible with a second codec and the codec A non-compatible mode is non-compatible with the second codec, the second codec being a legacy codec, the first terminal and the second terminal negotiate the codec A non-compatible mode in a session negotiation to select the codec A non-compatible mode to be used for the communication between the first terminal and the second terminal when the communication starts, and when the network node detects that the negotiated codec A non-compatible mode of the first terminal is switched to the codec A compatible mode or the second codec in the communication between the first terminal and the second terminal, the network node transmits a signal for the second terminal to switch the negotiated codec A non-compatible mode of the second terminal to the codec A compatible mode by a payload format of the first codec, and the second terminal switches the negotiated codec A non-compatible mode of the second terminal to the codec A compatible mode based on the signal.