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H.100 bus

A PCM digital bus standard for integrating hardware from various PC board vendors which enables boards to share voice data, signaling data, and switching information. The H.100 bus is an interoperable superset of the H-MVIP and MVIP-90 telephony buses. It can be addressed using the MVIP-95 switch model. See also bus, HMIC, H-MVIP, MVIP-90, MVIP-95.

H.110 bus

The Telephony bus which is a specific implementation of the H.100 bus streams and clocks, but redefines CT_NETREF as CT_NETREF_1 and adds CT_NETREF_2. It is implemented on a CompactPCI backplane at the J4 location. See CompactPCI, J1, J2, J3, J4, J5, CT_NETREF, CT_NETREF_1, CT_NETREF_2.

H.225

An ITU standard that defines opening and closing logical channels on a packet-switched network. H.225 is part of the H.323 standard for multimedia transmission over a packet-switched network. See also H.323, packet-switched network.

H.245

Under the H.323 standard, the channel used to transmit messages that control the operation of an H.323 terminal, including capability exchanges, commands, and indications. See also H.323.

H.261

The ITU standard that specifies the codec for videoconferencing. See also codec, H.323.

H.323

An application, network, and platform independent ITU standard that enables multimedia streaming over packet-switched networks. H.323 defines call control, codec standards, and channel setup for transmitting real-time audio and video streams over connectionless networks (including packet-switched networks, intranets, and the public Internet). H.323 includes the following IETF and ITU standards: H.225, H.245, H.261, G.711, G.722, G.723, G.728, G.729, Q.931, RAS, RTP (Real-time Transport Protocol). Any H.323 client must support the H.261 video codec standard and the G.711 PCM audio codec standard. See also circuit-switched network, codec, connectionless, H.225, H.245, H.261, IETF, ITU, G.711, G.722, G.723, G.728, G.729, packet-switched network, Q.931, RAS, RTP.

H-MVIP

The bus cable hardware standard for MVIP-95. See also MVIP-95.

half-call

A call from a circuit-switched or packet-switched network that has been connected from its origin to a midpoint, such as a telephony application on a host PC, but has not yet been connected to final destination.

half-duplex

A circuit that can carry information in both directions, but can only use one direction at a time. See also full-duplex, simplex.

HDLC

High Level Data Link Control; a link layer protocol for point-to-point and multi-port communications.

header

The portion of a message or packet that contains any sort of control, protocol, or address information.

high availability

Hot Swap system model requiring full Hot Swap boards and a high availability platform. In this model, the software can control the hardware connection process.

High Level Data Link Control

See HDLC.

HMIC

H.100/MVIP Integrated Circuit; the single chip that offers full support for the H.100 bus within the MVIP architecture, providing access to all 4096 timeslots on H.100 and H.110 buses. The industry standard name for the HMIC is the Lucent T8100. See also H.100 bus, H.110 bus.

host

The PC on which an application runs. Also used to designate a computer with full two-way access to a network such as local area network or the Internet.

hot swap

Ability to perform "live" insertion and removal of hardware components without disrupting the host system or application.

HS_CSR

Hot Swap Control/Status Register.

hybrid

A circuit that converts a single bidirectional communication channel to separate receive and transmit channels.