Tài liệu Definition - Copper Balanced Twisted Pair - from ISO 11801 ppt

ISO/IEC JTC 1/SC 25 N 739 2001-10-10 ISO/IEC JTC 1/SC 25N739t.doc 97 Annex E 2463 (informative)2464 2465 Acronyms for balanced cables2466 There is a great variety of cable constructions and a number of systems to describe these2467 constructions in a shortened form. These abbreviations have been used to describe the2468 difference in construction, as well the difference in impedance. Since such acronyms are used2469 in many commercial documents and have never been clearly specified by a standard, the same2470 term could mean different kinds of constructions in different context.2471 The intention of this annex is to clarify this situation and give guidance on how to use2472 abbreviations for the main constructions used for communication cables. This document uses2473 the words balanced cable, unscreened/screened cable and unscreened/screened cable2474 element for the cable constructions described in this annex.2475 To reduce confusion a more systematic naming is specified in Figure E. 1. It is understood that2476 cable names based on this schema only describe the types of constructions and not any2477 transmission characteristics such as impedance. All screened cables, whether individually or2478 overall, foiled, braided or both, require matching connecting hardware capable of handling all of2479 the screens involved.2480 Figure E. 2 gives examples of cable constructions and their name based on this schema.2481 xx / xxx | | |_ balanced element __ TP | |__ element screen ____ U = unscreened | |__ F = foil screened | |___ overall screen _____ F = foil screened |__ S = braid screen |_ SF =braid and foil screen For example: SF/UTP = overall braid and foil screened cable with unscreened balanced elements S/FTP = overall braid screened cable with foil screened balanced elements Figure E. 1 - Cable naming Schema2482 ISO/IEC JTC 1/SC 25 N 739 2001-10-10 ISO/IEC JTC 1/SC 25N739t.doc 98 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 Figure E. 2 - Cable Types2535 NOTE - sometimes the letter P in the abbreviation is replaced by Q to characterise a quad construction.2536 U/UTP: Cable sheath Pair Conductor F/UTP: Cable sheath Foil screen Pair Conductor SF/UTP: Cable sheath Braid screen Foil screen Pair Conductor S/FTP: Cable sheath Braid screen Foil pair screen Pair Conductor S/FTP: Cable sheath Braid screen Foil quad screen Quad Pair Conductor U/FTP: Cable sheath Foil pair screen Pair Conductor U/FTP: Cable sheath Foil quad screen Quad Pair Conductor U/UTP: Cable sheath Quad Pair Conductor . ISO/ IEC JTC 1/SC 25 N 739 200 1-1 0-1 0 ISO/ IEC JTC 1/SC 25N739t.doc 97 Annex E 2463 (informative)2464 2465 Acronyms for balanced cables2466. Quad Pair Conductor U/FTP: Cable sheath Foil pair screen Pair Conductor U/FTP: Cable sheath Foil quad screen Quad Pair Conductor U/UTP: Cable sheath Quad Pair