Balanced Technology Extended (BTX) Interface
Chassis Volumetric Zones
Figure 3-5 defines the footprint and height constraints that comprise the chassis volumetric zones as referenced from the top surface of the chassis pan. All components in a BTX-compatible system must adhere to the chassis volumetric zones according to the requirements in following table.
Table 3-4. Categories and Requirements for Chassis Zones
Category | Examples | Requirements |
Motherboard components | Memory modules, processors, rear panel motherboard connectors and rigid portions of motherboard-terminated cable assemblies, component heatsinks, and components soldered to motherboard | Must not intersect any of the chassis volumetric zones at any point. In addition, adequate clearance should be provided between installed system components and the chassis volumetric to avoid component interface and/or damage during shipping or other dynamic conditions. |
Chassis components | Chassis pan, board mounting features and drive bays | Must not intersect volumetric zones F, G, or H. Chassis features in Zone K must not cross the upper boundary of Zone K. Only the interface features called out in and are allowed in Zones F, G, H, and J. No other chassis features should intersect this zone. Board mounting features should stay within the zones specified for these features. |
Transition components | SRM and Thermal Module | May cross the outer boundary of some chassis zones. Components such as an SRM may have their own requirements which should be considered by the designer in addition to these specified in this document. |
Other System components | Disk drives and system power supply | Must not intersect any of the chassis volumetric zones at any point. In addition, adequate clearance should be provided between installed system components and the chassis volumetric to avoid component interface and/or damage during shipping or other dynamic conditions. |