The 307 utilises the latest Multiplex technology, developed inconjunction with PSA partner Citroen, Bosch and Renault. PSA firsttrialled this system back in 1994 on the Citroen XM. With all the features now available in modern cars, the amount ofwiring required has become enormous. Electrical connections havegone up from around 200 to over 1000 in a modern car, resulting in aspaghetti like mess around the car. Instead of so many wires, amultiplexed system of 4 BUSes (containing 4 wires each) is used. These BUSes provide electric power to the various components aroundthe car, as well as sending individual digitally encoded messages foreach component. The car has 18 microprocessors. The system is comprised of two networks, the faster 250kbps CAN(controller area network) and the slower VAN (vehicle area network),which are bridged by the BSI/ISB (built in systems interface/intelligentservice box). BSI stands for Boîtier de Servitude Intelligent.