Words that end in sdna
Maybe these words will be useful:
- psdn — (communications) Public Switched Data Network.
- euro-isdn — European Integrated Services Digital Network. An ETSI standard for Integrated Services Digital Network being phased in in March 1994. Euro-ISDN will allow full transparent interworking between all European countries (members of the CEPT). It is available on a commercial basis in most European countries.
- isdn — (communications) (ISDN) A set of communications standards allowing a single wire or optical fibre to carry voice, digital network services and video. ISDN is intended to eventually replace the plain old telephone system. ISDN was first published as one of the 1984 ITU-T Red Book recommendations. The 1988 Blue Book recommendations added many new features. ISDN uses mostly existing Public Switched Telephone Network (PSTN) switches and wiring, upgraded so that the basic "call" is a 64 kilobits per second, all-digital end-to-end channel. Packet and frame modes are also provided in some places. There are different kinds of ISDN connection of varying bandwidth (see DS level): DS0 = 1 channel PCM at 64 kbps T1 or DS1 = 24 channels PCM at 1.54 Mbps T1C or DS1C = 48 channels PCM at 3.15 Mbps T2 or DS2 = 96 channels PCM at 6.31 Mbps T3 or DS3 = 672 channels PCM at 44.736 Mbps T4 or DS4 = 4032 channels PCM at 274.1 Mbps Each channel here is equivalent to one voice channel. DS0 is the lowest level of the circuit. T1C, T2 and T4 are rarely used, except maybe for T2 over microwave links. For some reason 64 kbps is never called "T0". A Basic Rate Interface (BRI) is two 64K "bearer" channels and a single "delta" channel ("2B+D"). A Primary Rate Interface (PRI) in North America and Japan consists of 24 channels, usually 23 B + 1 D channel with the same physical interface as T1. Elsewhere the PRI usually has 30 B + 1 D channel and an E1 interface. A Terminal Adaptor (TA) can be used to connect ISDN channels to existing interfaces such as EIA-232 and V.35. Different services may be requested by specifying different values in the "Bearer Capability" field in the call setup message. One ISDN service is "telephony" (i.e. voice), which can be provided using less than the full 64 kbps bandwidth (64 kbps would provide for 8192 eight-bit samples per second) but will require the same special processing or bit diddling as ordinary PSTN calls. Data calls have a Bearer Capability of "64 kbps unrestricted". ISDN is offered by local telephone companies, but most readily in Australia, France, Japan and Singapore, with the UK somewhat behind and availability in the USA rather spotty. (In March 1994) ISDN deployment in Germany is quite impressive, although (or perhaps, because) they use a specifically German signalling specification, called 1.TR.6. The French Numeris also uses a non-standard protocol (called VN4; the 4th version), but the popularity of ISDN in France is probably lower than in Germany, given the ludicrous pricing. There is also a specifically-Belgian V1 experimental system. The whole of Europe is now phasing in Euro-ISDN. See also Frame Relay, Network Termination, SAPI.
- bisdn — Broadband Integrated Services Digital Network.
- dhsd — Duplex High Speed Data
- ulsd — Ultra Low Sulphur Diesel
- mcsd — Microsoft Certified Solution Developer
- msd — Ministry of Social Development
- sd — structured design
- freebsd — (operating system) A free operating system based on the BSD 4.4-lite release from Computer Systems Research Group at the University of California at Berkeley. FreeBSD requires an ISA, EISA, VESA, or PCI based computer with an Intel 80386SX to Pentium CPU (or compatible AMD or Cyrix CPU) with 4 megabytes of RAM and 60MB of disk space. Some of FreeBSD's features are: preemptive multitasking with dynamic priority adjustment to ensure smooth and fair sharing of the computer between applications and users. Multiuser access - peripherals such as printers and tape drives can be shared between all users. Complete TCP/IP networking including SLIP, PPP, NFS and NIS. Memory protection, demand-paged virtual memory with a merged VM/buffer cache design. FreeBSD was designed as a 32 bit operating system. X Window System (X11R6) provides a graphical user interface. Binary compatibility with many programs built for SCO, BSDI, NetBSD, 386BSD, and Linux. Hundreds of ready-to-run applications in the FreeBSD ports collection. FreeBSD is source code compatible with most popular commercial Unix systems and thus most applications require few, if any, changes to compile. Shared libraries. A full compliment of C, C++, Fortran and Perl development tools and many other languages. Source code for the entire system is available. Extensive on-line documentation.