Primary rate interface
(PRI) A type of ISDN connection. In North America and Japan, this consists of 24 channels, usually divided into 23 B channels and 1 D channel, and runs over the same physical interface as T1. Elsewhere the PRI has 31 user channels, usually divided into 30 B channels and 1 D channel and is based on the E1 interface.
PRI is typically used for connections such as one between a PBX (private branch exchange, a telephone exchange operated by the customer of a telephone company) and a CO (central office, of the telephone company) or IXC (inter exchange carrier, a long distance telephone company).
(1995-01-18)
Read Also:
- Primary reaction
primary reaction n. See vaccinia.
- Primary-root
noun, Botany. 1. the first root produced by a germinating seed, developing from the radicle of the embryo. primary root The first root of a plant, originating in the embryo. In gymnosperms, eudicotyledons, and magnoliids, the primary root develops into the taproot. In monocotyledons, the primary root disintegrates as the lateral roots develop into a […]
- Primary-school
noun 1. a school usually covering the first three or four years of elementary school and sometimes kindergarten. 2. elementary school. primary school noun 1. (in Britain) a school for children below the age of 11. It is usually divided into an infant and a junior section 2. (in the US and Canada) a school […]
- Primary-sex-characteristic
noun, Anatomy. 1. any of the body structures directly concerned in reproduction, as the testes, ovaries, and external genitalia.
- Primary-spermatocyte
noun, Cell Biology. 1. See under spermatocyte. spermatocyte [spur-mat-uh-sahyt, spur-muh-tuh-] /spɜrˈmæt əˌsaɪt, ˈspɜr mə tə-/ noun, Cell Biology. 1. a male germ cell (primary spermatocyte) that gives rise by meiosis to a pair of haploid cells (secondary spermatocytes) that give rise in turn to spermatids. spermatocyte /ˈspɜːmətəʊˌsaɪt/ noun 1. (zoology) an immature male germ cell, […]