T.140 Subtitles support sending and receiving subtitles from SIP, H.323 type terminals.

HD terminals support peer-to-peer () calling. (3 answers).

Image format refers to the size or resolution size of the image, common image formats include, SOCIF, QCIF, CIF, ACIF, 16CIF, HD, Full HD. ( )

Due to the size of the display and the resource limitations of the MCU , the number of multi-screen sprites generally does not exceed 24 , otherwise the image is too small and the picture will not be clear.

For reverberation, the pickup is dominated by a direct sound, and the appropriate amount of reverberation sounds thicker, and it is recommended that the pickup direct sound be around 90%.
However, the reverberation sound after 50ms will affect the language comprehensibility, and it is recommended that the sound energy reached within 50ms accounts for more than 80%.