International standard ISO/IEC 11801 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 corresponding standard for small-office/home-office (SOHO) environments is ISO/IEC 15018, which also covers 1.2 GHz links for cable and satellite TV applications.
Link and channel classes
The standard defines several classes of twisted-pair copper interconnects, which differ in the maximum frequency for which a certain channel performance is required:
- Class A: up to 100 kHz using elements category 1
- Class B: up to 1 MHz using elements category 2
- Class C: up to 16 MHz using elements category 3
- Class D: up to 100 MHz using elements category 5e
- Class E: up to 250 MHz using elements category 6
- Class EA: up to 500 MHz using elements category 6A (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.)
- Class F: up to 600 MHz using elements category 7
- Class FA: up to 1000 MHz using elements category 7A (Amendment 1 and 2 to ISO/IEC 11801, 2nd Ed.)
The standard link impedance is 100 Ω. (The older 1995 version of the standard also permitted 120 Ω 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 1db/km attenuation
- OS2: Single-mode fiber type 0.4db/km attenuation
Class F cable
Class F cable (or, unofficially, Category 7 cable) is a cable standard for Ethernet and other interconnect technologies that can be made to be backward compatible with Class D and Class E. Class F features even more strict 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 foil shield, the twisting of the pairs and number of turns per unit length increases RF shielding and protects from crosstalk. Class F is recognized for all the country organizations members of ISO.
The Class F 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. Class F can be terminated either with 8P8C compatible GG45 electrical connectors which incorporate the 8P8C standard or with TERA connectors. When combined with GG45 or TERA connectors, Class F cable is rated for transmission frequencies of up to 600 MHz.
As of November 2010[update], all manufacturers of active equipment have chosen to support the 8P8C for their 10 Gigabit Ethernet products on copper and not the GG45 or TERA in order to function on Cat 6a. Class F is not currently recognized by the TIA/EIA.
Class FA (or Augmented Class F or, unofficially, Category 7a) is defined at frequencies up to 1000 MHz, suitable for multiple applications including CATV (862 MHz). Each pair offers 1200 MHz of bandwidth. Simulation results have shown that 40 Gigabit Ethernet may be possible at 50 meters (164 ft) and 100 Gigabit Ethernet at 15 meters (49 ft). 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(328 ft).
As of May 2013[update], the IEEE TR42.7 has now defined that 40 Gigabit Ethernet will require a new cabling system defined up to 2 GHz, currently called Category 8. Furthermore the application will use the standard 8P8C connector. Class Fa / Category 7a will therefore not be compatible with the next generation Ethernet application.
Class F is currently in ISO standards for channel performance in Amendment 1, and component performance in Amendment 2. The formal names are ISO 11801 Amendment 1 (2008) and ISO 11801 Amendment 2 (2010). Class Fa is not recognized in TIA/EIA-568.
- Nielsen, Allan (2008), AMP NETCONNECT Guide to ISO/IEC 11801 2nd Edition Including Amendment 1 (pdf), Schaffhausen, Switzerland: Tyco Electronics, p. 11, retrieved March 11, 2012
- "Researchers push transmission rate of copper cables". News release (Pennsylvania State University). November 14, 2007. Retrieved July 9, 2011.
- Rick C. Hodgin (November 14, 2007). "UPDATE: Cat-7 copper theorized to transmit 100 Gbit/s in excess of 100 meters (328 ft) using future modems". TGDaily blog. Retrieved July 9, 2011.
- publisher = Cabling Installation & Maiintenance
- International standard ISO/IEC 11801: Information technology — Generic cabling for customer premises.
- European standard EN 50173: Information technology — Generic cabling systems. 1995.