IEEE Std 1394b-2002 is a full-use standard whose scope is to provide an amendment to IEEE Std 1394-1995 and a companion to IEEE Std 1394a-2000. This amendment defines features and mechanisms that provide gigabit speed extensions in a backwards compatible fashion and the ability to signal over single hop distances of up to 100 m.The following are included in IEEE Std 1394b-2002:a) Cables and connectors for gigabit signaling and long distance (up to 100 m);b) Detection of physical loops in the bus topology and their subsequent resolution by selective disabling of physical layer (PHY) port(s);c) The same circuits may be used to transmit either data-strobe (DS) signals or SB/lOB-encoded signals;d) Extension of the PHY-link interface to higher data rates over an 8 bit parallel bus;e) Extension of the PHY-link interface to higher data rates over a bit-serial bus;f) Definition of high-speed bit protocols to handle various bus arbitration signals and the transport of slower data packets by bit-stuffed@ high-speed packets;g) Protocols for signal speed matching at connect time;h) Port initialization protocols suitable for use over ac-coupled connections; andi) Various informative annexes to discuss testing and compliance procedures for gigabit connections.The preceding are arranged in no particular order.PurposeTechnology advances have made gigabit signaling a feasible and attractive extension to the baseline standard@ IEEE Std 1394-1995. In particular@ the needs of data storage and home backbones dictate a higher speed and longer distance interconnect bus than can be provided by IEEE Std 1394-1995 and IEEE Std 1394a-2000.