| H.320 / H.323 | |
| Sets of widely-used CCITT video compression standards describing methods to allow videoconferencing systems from different manufacturers to interoperate. They include a number of individual recommendations for coding, framing, signalling and establishing connections. Three audio algorithms, G.721, G.722 and G.728, are also included in the standards. | |
| Half duplex audio | |
| 2-way audio transmitted and received in turn (rather than simultaneously) so only one site can speak at a time. Contrast with full duplex audio. | |
| Handshake | |
| Prior to a videoconferencing transmission, the codecs exchange predetermined electrical signals that allow them to interoperate by they seeking out a common algorithm. | |