This part of IEC 61 1 56 describes cables primarily intended for the fixed part of channels as defined in ISO/IEC 1 1 801 and in ISO/IEC TR 1 1 801 -9901 which is planned to be included in the next edition of ISO/IEC 1 1 801 -1 . It covers overall screened cables with screened (X/FTP) or unscreened (X/UTP) pairs, where X stands for F, S or SF, as well as pair-screened cables without overall screen (U/FTP). The transmission characteristics of these cables are specified up to a frequency of 2 000 MHz and at a temperature of 20 °C. Two categories of cables are recognised:
• Category 8.1 for use in Class I according to ISO/IEC TR 1 1 801 -9901 ;
• Category 8.2 for use in Class II according to ISO/IEC TR 1 1 801 -9901 .
These cables are intended to be used for communication channels which use at least four pairs simultaneously.
The cables covered by this International Standard are intended to operate with voltages and currents normally encountered in communication systems. While these cables are not intended to be used in conjunction with low impedance sources, e.g. the electric power supplies of public utility mains, they are intended to be used to support the delivery of low voltage remote powering applications such as IEEE 802.3af (Power over Ethernet) or further developments e.g. according to IEEE 802.3at or IEEE 802.3bt. More information on the capacity to support these applications according to the installation practices is given in IEC PAS 61 1 56-1 -4, IEC TR 61 1 56-1 -6 and ISO/IEC TR 291 25.
