H.320

Also known as Px64.The ITU-T umbrella standard for videoconferencing and multimedia communications over narrowband ISDN (N-ISDN) bearer (B) channels at bit rates from 64 kbps to 1.920

Mbps, in increments of 64 kbps.Video compression makes use of codecs defined in H.261.Video formats include Common Intermediate Format (CIF), which is optional, and Quarter-CIF (QCIF), which is mandatory in compliant codecs. CIF supports resolution of 352 × 288 pixels, and QCIF supports resolution of 176 × 144 pixels, which is exactly 1⁄4 the resolution of CIF. Frame rates are 30 frames per second (fps), or lower. Audio coding and compression recommendations include G.711, which is pulse code modulation (PCM) at 64 kbps. G.722 is high fidelity adaptive differential pulse code modulation (ADPCM) transmitting up to a 7 kHz range and compressing voice at 48/56/64 kbps. G.728 specifies low delay code-excited linear prediction (LD-CELP) running in the 3 kHz range and compressing voice at 16 kbps.

The balance of the specification (H.221, H.230, and H.242) addresses techniques for call setup and teardown, data framing and multiplexing, and various other operational and administrative functions. See also

74570c08.qxd 9/11/07 12:21 PM Page 218

• SSL (Secure Sockets Layer)
• SSP (Service Switching Point)
• standard
• Standard Generalized Markup Language (SGML)
• Standard Wire Gauge (SWG)
• start bit
• star topology
• start-stop transmission
• stateful
• stateful autoconfiguration
• stateful autoconfiguration
• stateful autoconfiguration
• stateful inspection firewall
• stateless
• stateless autoconfiguration
• static address
• static bend
• static load
• station
• station message detail record (SMDR)
• statistical time division multiplexer (STDM mux or stat mux)
• statistical time division multiplexing (STDM)
• stat mux (statistical time division multiplexer)
• STDM (Statistical Time Division Multiplexing)
• steer