Originally developed for the Eurofighter, STANAG 3910 was based on the MIL-STD-1553 with the addition of a high speed fibre optic bus. This was driven by the need for higher transfer rates than was possible with the One Mbps speed of MIL-STD-1553. This tutorial provides a general overview of STANAG 3910, its specifications and applications. A short history of the standard is presented. The paper then explains the topology of both the low speed (MIL-STD-1553) and high speed (Fibre Optic) buses. The message formats are described in detail. Finally, testing and validation of systems that operate on the bus are discussed.