International standard ISO/IEC 11801 Information technology â€" Generic cabling for customer premises specifies general-purpose telecommunication cabling systems (structured cabling) that are suitable for a wide range of applications (analog and ISDN telephony, various data communication standards, building control systems, factory automation). It covers both balanced copper cabling and optical fibre cabling.
The standard was designed for use within commercial premises that may consist of either a single building or of multiple buildings on a campus. It was optimized for premises that span up to 3 km, up to 1 km2 office space, with between 50 and 50,000 persons, but can also be applied for installations outside this range.
A major revision, Edition 3, is being prepared which will unify requirements for commercial, home and industrial networks.
Classes and categories
The standard defines several link/channel classes and cabling categories of twisted-pair copper interconnects, which differ in the maximum frequency for which a certain channel performance is required:
- Class A: link/channel up to 100 kHz using Category 1 cable/connectors
- Class B: link/channel up to 1 MHz using Category 2 cable/connectors
- Class C: link/channel up to 16 MHz using Category 3 cable/connectors
- Class D: link/channel up to 100 MHz using Category 5e cable/connectors
- Class E: link/channel up to 250 MHz using Category 6 cable/connectors
- Class EA: link/channel up to 500Â MHz using Category 6A cable/connectors (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.)
- Class F: link/channel up to 600 MHz using Category 7 cable/connectors
- Class FA: link/channel up to 1000 MHz using Category 7A cable/connectors (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.)
- Class I: link/channel up to between 1600 and 2000 MHz using Category 8.1 cable/connectors (specification under development)
- Class II: link/channel up to between 1600 and 2000 MHz using Category 8.2 cable/connectors (specification under development)
The standard link impedance is 100 Ω (The older 1995 version of the standard also permitted 120vΩ and 150 Ω in Classes Aâˆ'C, but this was removed from the 2002 edition).
The standard defines several classes of optical fiber interconnect:
- OM1: Multimode fiber type 62.5 µm core; minimum modal bandwidth of 200 MHz·km at 850 nm
- OM2: Multimode fiber type 50 µm core; minimum modal bandwidth of 500 MHz·km at 850 nm
- OM3: Multimode fiber type 50 µm core; minimum modal bandwidth of 2000 MHz·km at 850 nm
- OM4: Multimode fiber type 50 µm core; minimum modal bandwidth of 4700 MHz·km at 850 nm
- OS1: Single-mode fiber type 1Â dB/km attenuation
- OS2: Single-mode fiber type 0.4Â dB/km attenuation
Category 7
Class F channel and Category 7 cable are backward compatible with Class D/Category 5e and Class E/Category 6. Class F features even stricter specifications for crosstalk and system noise than Class E. To achieve this, shielding has been added for individual wire pairs and the cable as a whole. Besides the shield, the twisting of the pairs and number of turns per unit length increases RF shielding and protects from crosstalk.
The Category 7 cable standard has been created to allow 10 Gigabit Ethernet over 100 m of copper cabling (also, 10 Gbit/s Ethernet now is typically run on Cat 6A). The cable contains four twisted copper wire pairs, just like the earlier standards. Category 7 cable can be terminated either with 8P8C compatible GG45 electrical connectors which incorporate the 8P8C standard or with TERA connectors. When combined with GG-45 or TERA connectors, Category 7 cable is rated for transmission frequencies of up to 600 MHz.
As of November 2010, all manufacturers of active equipment have chosen to support the 8P8C for their 10 Gigabit Ethernet products on copper and not the GG45, ARJ45, or TERA in order to function on Cat 6A.
Category 7 is not recognized by the TIA/EIA.
Category 7A
Class FA (Class F Augmented) channels and Category 7A cables, introduced by ISO 11801 Edition 2 Amendment 2 (2010), are defined at frequencies up to 1000Â MHz, suitable for multiple applications including CATV (862Â MHz). Each pair offers 1200Â MHz of bandwidth.
Simulation results have shown that 40 Gigabit Ethernet may be possible at 50Â meters and 100Â Gigabit Ethernet at 15Â meters. In 2007, researchers at Pennsylvania State University predicted that either 32Â nm or 22Â nm circuits would allow for 100Â Gigabit Ethernet at 100Â meters.
Category 7A is not recognized in TIA/EIA-568.
Category 8
In March 2013, technical recommendation ISO/IEC TR 11801-99-1, issued by ISO/IEC JTC 1 computer interconnect and premises cabling group SC25 WG3, defined two new categories for 4-pair copper twisted pair cable with 2 connectors, with operating frequency up to 1600Â MHz and possible overhead for 2000Â MHz:
- Class I channel (Category 8.1 cable): minimum cable design U/FTP or F/UTP, fully backward compatible and interoperable with Class EA (Category 6A) using 8P8C connectors
- Class II channel (Category 8.2 cable): F/FTP or S/FTP minimum, interoperable with Class FA (Category 7A) using 8P8C or TERA/GG-45/ARJ-45 connectors
Also in March 2013, technical recommendation TIA TR42.7 defined that 40GBASE-T will require a new cabling system defined to at least 1.6 GHz and up to 2 GHz, currently called Category 8, which will use the standard 8P8C connector. Category 8 should be fully backward compatible with Category 6A and below, and will be covered by ANSI/TIA-568-C.2-1 "Specifications for 100 Ω Category 8 Cabling".
As of January 2014, draft versions of ISO/IEC TR 11801-99-1 and ANSI/TIA-568-C.2-1 have been aligned to reduce the difference between Categories 8, 8.1 and 8.2. The final specifications will depend on transceiver requirements to be defined by IEEE 802.3bq (40GBASE-T) workforce.
Acronyms for twisted pairs
Annex E, Acronyms for balanced cables, provides a system to specify the exact construction for both unshielded and shielded balanced twisted pair cables. It uses three letters - U for unshielded, S for braided shielding, and F for foil shielding - to form a two-part abbreviation in the form of xx/xTP, where the first part specifies the type of overall cable shielding, and the second part specifies shielding for individual cable elements.
Common cable types include U/UTP (unshielded cable); U/FTP (individual pair shielding without the overall screen); F/UTP, S/UTP, or SF/UTP (overall screen without individual shielding); and F/FTP, S/FTP, or SF/FTP (overall screen with individual foil shielding).
Edition 3
Edition 3, currently being prepared by ISO/IEC JTC 1/SC 25 "Interconnection of information technology equipment", is a major revision of the standard which will unify several prior standards for commercial, home, and industrial networks, as well as data centers, and define requirements for generic cabling and distributed building networks.
The new series of standards will include six parts:
Versions
- ISO/IEC 11801:1995 (Ed. 1) - first edition
- ISO/IEC 11801:2000 (Ed. 1.1) - Edition 1, Amendment 1
- ISO/IEC 11801:2002 (Ed. 2) - second edition
- ISO/IEC 11801:2008 (Ed. 2.1) - Edition 2, Amendment 1
- ISO/IEC 11801:2010 (Ed. 2.2) - Edition 2, Amendment 2
- ISO/IEC 11801 Ed.3 (in development)
See also
- Ethernet over twisted pair
- Twisted pair
- TIA/EIA-568
- ISO/IEC JTC 1/SC 25
References
Further reading
- International standard ISO/IEC 11801: Information technology â€" Generic cabling for customer premises.
- European standard EN 50173: Information technology â€" Generic cabling systems. 1995.