ISO/IEC 11801

International standard ISO/IEC 11801 Information technology — 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 E_A: link/channel up to 500 MHz using Category 6_A 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 F_A: link/channel up to 1000 MHz using Category 7_A 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 A−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 1 dB/km attenuation
• OS2: Single-mode fiber type 0.4 dB/km attenuation

Category 7

Category 7 S/FTP cable

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. Unshielded cables rely on the quality of the twists to protect from EMI. This involves a tight twist and carefully controlled design. Cables with individual shielding per pair such as category 7 rely mostly on the shield and therefore have pairs with longer twists.

The Category 7 cable standard has been ratified in 2002 to allow 10 Gigabit Ethernet over 100 m of copper cabling. 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.^[1]

However, in 2008 Category 6_A was ratified and allows 10 Gbit/s Ethernet while still using the traditional 8P8C connector (also called RJ45). Therefore, all manufacturers of active equipment and network cards have chosen to support the 8P8C for their 10 Gigabit Ethernet products on ^[2] copper and not the GG45, ARJ45, or TERA. These products therefore require a Class E_A channel (Cat 6_A). As of 2017 there is no equipment that has connectors supporting the Class F (Category 7) channel.

Category 7 is not recognized by the TIA/EIA.

Category 7_A

Class F_A (Class F Augmented) channels and Category 7_A cables, introduced by ISO 11801 Edition 2 Amendment 2 (2010), are defined at frequencies up to 1000 MHz, suitable for multiple applications including CATV (862 MHz).

The intent of the Class FA was to possibly support the future 40Gigabit Ethernet: 40Gbase-T. Simulation results have shown that 40 Gigabit Ethernet may be possible at 50 meters and 100 Gigabit Ethernet at 15 meters. In 2007, researchers at Pennsylvania State University predicted that either 32 nm or 22 nm circuits would allow for 100 Gigabit Ethernet at 100 meters.^[3][4]

However, in 2016, the IEEE 802.3bq working group ratified the amendment 3 which defines 25Gbase-T and 40gbase-T on Category 8 cabling specified to 2000 MHz. The Class FA therefore does not support 40G Ethernet.

As of 2017 there is no equipment that has connectors supporting the Class F (Category 7) channel.

Category 7_A is not recognized in TIA/EIA-568.

Category 8

Category 8 was ratified by the TR43 working group under ANSI/TIA 568-C.2-1. It is defined up 2000 MHz and only for distances from 30 to 36m depending on the patch cords used. ISO is expected to ratify the equivalent in 2017 or 2018 but will have 2 options:

• Class I channel (Category 8.1 cable): minimum cable design U/FTP or F/UTP, fully backward compatible and interoperable with Class E_A (Category 6_A) using 8P8C connectors
• Class II channel (Category 8.2 cable): F/FTP or S/FTP minimum, interoperable with Class F_A (Category 7_A) using TERA or GG45 connectors.

Category 8 is designed only for data centers where distances between switches and servers is short. It is not intended for general office cabling.

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:^[5][6]

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 — Generic cabling for customer premises.
• European standard EN 50173: Information technology — Generic cabling systems. 1995.