knowledge of the vehicle was needed to be able to select the correct gear, transfer ratio, various differential systems and master various techniques required for tackling steep hills, deep water and other tough terrain. Terrain Response attempted to take away as many of the difficulties as possible. The driver selected a terrain type ("Sand", "Grass, Gravel & Snow", "Mud & Ruts" and "Rock Crawl") on a dial in the cab of the vehicle. The on-board computer systems then select the correct gearbox settings, adjust the suspension height, adjust the differential lock settings and even alter the throttle response of the engine suitable for the terrain. For example, in "Rock Crawl", the suspension is raised to its maximum height and set to allow maximum wheel articulation, the differentials are locked, the driver is prompted to switch to Low Range, and the throttle response is altered to provide low-speed control. In "Sand" mode, the traction control system is 'primed' to be more sensitive to wheelspin, the differentials are partly locked, and the throttle response is re-mapped to produce high power outputs with short pedal movement. The driver retained some manual control over the off-road systems, being able to select the Transfer Box ratio and the suspension height manually, although use of the Terrain Response system is needed to allow full use of the vehicles' capabilities. As well as new mechanical and electronic systems, the Discovery 3 introduced a new design to the interior and exterior of the vehicle. The Discovery 3 was able to have a fresh, minimalist style. The interior featured a flexible seven-seat layout. Passengers in the rearmost row now entered through the rear side doors, instead of the tailgate as in previous versions. The driver benefitted from a DVD navigation system, including some optional features like Bluetooth telephony in later models. Like the Range Rover, this audio, information & entertainment ("infotainment") system in the Discovery 3 adopted an electronics architecture whereby the system's distributed control units pass information and audio amongst one another and throughout the vehicle via optical links based on the MOST (or, Media Oriented Systems Transport) fibre-optic automotive networking standard (informally called the "MOST-bus"). The system's navigation functions were unique to Land Rover because, in addition to the typical road map navigation, benefits included an off-road navigation and four-wheel drive information mode. When in four-wheel drive information mode, the screen showed a schematic of the vehicle,