Tham khảo tài liệu 'definition - copper balanced twisted pair - from iso 11801', công nghệ thông tin, quản trị mạng phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ISO/IEC JTC 1/SC 25 N 739 2001-10-10 2463 Annex E 2464 (informative) 2465 2466 Acronyms for balanced cables 2467 There is a great variety of cable constructions and a number of systems to describe these 2468 constructions in a shortened form. These abbreviations have been used to describe the 2469 difference in construction, as well the difference in impedance. Since such acronyms are used 2470 in many commercial documents and have never been clearly specified by a standard, the same 2471 term could mean different kinds of constructions in different context. 2472 The intention of this annex is to clarify this situation and give guidance on how to use 2473 abbreviations for the main constructions used for communication cables. This document uses 2474 the words balanced cable, unscreened/screened cable and unscreened/screened cable 2475 element for the cable constructions described in this annex. 2476 To reduce confusion a more systematic naming is specified in Figure E. 1. It is understood that 2477 cable names based on this schema only describe the types of constructions and not any 2478 transmission characteristics such as impedance. All screened cables, whether individually or 2479 overall, foiled, braided or both, require matching connecting hardware capable of handling all of 2480 the screens involved. 2481 Figure E. 2 gives examples of cable constructions and their name based on this schema. 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 2482 Figure E. 1 - Cable naming Schema ISO/IEC JTC 1/SC 97 ISO/IEC JTC 1/SC 25 N 739 2001-10-10 2483 2484 2485 U/UTP: U/UTP: 2486 2487 Cable sheath Cable sheath 2488 Pair Quad 2489 Pair 2490 .
