A gigabit interface converter (GBIC) is a standard for transceivers, commonly used with Gigabit Ethernet and fibre channel. By offering a standard, hot swappable electrical interface, one gigabit ethernet port can support a wide range of physical media, from copper to long-wave single-mode optical fiber, at lengths of hundreds of kilometers.
The appeal of the GBIC standard in networking equipment, as opposed to fixed physical interface configurations, is its flexibility. Where multiple different optical technologies are in use, an administrator can purchase GBICs as needed, not in advance, and they can be the specific type needed for each link. This lowers the cost of the base system and gives the administrator far more flexibility. On the other hand if it is known that a switch will mostly have one port type (especially if that port type is copper) purchasing a switch with that port type built in will probably be cheaper and take up less space per port.
The GBIC standard is non-proprietary and is defined by the SFF Committee in document # SFF-8053.
