Packaging high-density cards within a controlled rack envelope
Compact electronic systems often have to satisfy several mechanical and electrical requirements at the same time: accommodate full-height circuit cards, preserve access to rear I/O, maintain airflow through a dense card population, and fit within a standard equipment rack.
The Vector Series 2270 addresses this combination through a horizontal card chassis architecture available in 1U, 2U, 3U, and 4U configurations. The chassis is designed for 6U-height VME, VME64x, CompactPCI, or VPX systems, while maintaining a compact 19-inch rackmount footprint.
This format is useful when a system requires the card capacity and backplane flexibility of a 6U platform but cannot use the greater vertical space associated with a conventional vertical-card enclosure.
Mechanical architecture
The Series 2270 uses two horizontal card cages:
- A 6U x 160 mm front card cage for primary circuit cards
- A 6U x 80 mm rear card cage for rear transition modules
The front cage provides the main card installation area. The separate rear cage allows transition modules to be positioned behind the primary cards, preserving a direct relationship between front-board functions and rear-panel connectivity.
This arrangement separates circuit-card installation from external cabling and I/O access. In a typical system, a front card can perform processing, switching, acquisition, or control functions while its associated rear transition module provides connectors, signal breakout, or application-specific interface circuitry at the rear of the chassis.
The enclosure accepts a 6U-high VME, VME64x, cPCI, or VPX backplane. Backplane selection therefore becomes a system-level decision rather than a limitation imposed by the chassis format. The backplane can be specified according to the bus architecture, slot count, connector arrangement, power distribution, and signal-integrity requirements of the application.
The mechanical design is compliant with:
- IEEE 1101.1
- IEEE 1101.10
- IEEE 1101.11
These standards define important aspects of Eurocard and board-support mechanics, including card dimensions, front-panel interfaces, injector/ejector provisions, and related subrack construction requirements. Compliance helps establish a predictable mechanical interface between circuit cards, card guides, front panels, and the backplane.
Rack density across four chassis heights
The Series 2270 is offered in four rack heights:
| Version | Chassis height | Approximate metric height |
|---|---|---|
| 1U | 1.72 in. | 43.69 mm |
| 2U | 3.47 in. | 88.14 mm |
| 3U | 5.22 in. | 132.59 mm |
| 4U | 6.97 in. | 177 mm |
All versions use a 19-inch rackmount width, with mounting defined according to EIA-310-D. The chassis depth is 11.65 inches (296 mm), excluding the rack handle.
The height selection allows the enclosure to be matched to the usable card population, power architecture, cooling requirement, and available rack space. A 1U implementation can be used where vertical density is the primary constraint. A 4U implementation provides more internal volume for card capacity, power modules, cabling, or application-specific mechanical modifications.
Rack height should be evaluated together with the complete system stack-up. The chassis must accommodate the card cage, backplane, power modules, cooling path, rear transition modules, front-panel hardware, and any cable or connector clearance required at the rear. Nominal rack units alone do not determine whether a completed assembly will be serviceable.
Push-pull airflow through a horizontal card system
Horizontal card packaging changes the airflow problem compared with a conventional front-to-rear vertical-card chassis. The cooling path must move air across the card population while avoiding recirculation around the card cages, power assemblies, and rear transition modules.
The Series 2270 uses a side-to-side cooling path:
- Left side: air intake
- Right side: air exhaust
- Fixed embedded fans on both sides
- Push-pull fan arrangement
The left-side fans introduce ambient air into the enclosure, while the right-side fans assist in pulling heated air through the system and exhausting it. This push-pull arrangement supports a more controlled air path across the horizontal card assembly than relying on a single fan bank at one side of the chassis.
For system integrators, the airflow direction has several practical consequences. Rack installation must preserve clearance at both sides of the enclosure. Adjacent equipment, cable bundles, side panels, or rack obstructions should not block the intake or exhaust openings. The rack-level cooling plan must also account for the temperature of the air entering the left side and the effect of neighboring equipment on the right-side exhaust environment.
The fixed embedded fan configuration avoids dependence on a removable external fan tray. It also places the cooling hardware directly within the chassis airflow path. Fan monitoring, acoustic requirements, filter provisions, and fan life expectations should be considered during system definition, particularly for installations requiring continuous operation or scheduled maintenance.
The published environmental specifications are:
- Operating temperature: 0°C to 50°C
- Non-operating temperature: –40°C to 75°C
- Humidity: 5% to 95%, non-condensing
- Flammability: UL94V-0
These ratings describe the stated chassis environment and material specification. They do not replace a thermal analysis of the installed electronics. Actual operating temperature limits may be governed by the circuit cards, processors, power modules, connectors, or other system components.
Rear transition modules and service access
Rear transition modules are valuable when a system requires dense external connectivity without routing individual cables from every front card through the chassis interior. The Series 2270’s 6U x 80 mm rear cage creates a dedicated region for this interface hardware.
A rear transition-module architecture can simplify several service tasks:
- I/O replacement: External connectors remain associated with the rear module rather than being permanently wired to the front card.
- Cable organization: Rear-panel cabling is consolidated at the back of the chassis.
- Card maintenance: Front cards can be removed from the primary cage without disturbing every external interface cable.
- Configuration control: The front card, rear transition module, and backplane can be documented as a defined system assembly.
- System integration: Application-specific I/O can be adapted through transition modules while retaining the basic enclosure and backplane structure.
Access planning remains important. Card ejectors, front panels, rear transition modules, power supplies, and cable connectors all require adequate clearance. A compact chassis achieves high rack density only when the installed configuration remains accessible for inspection, replacement, and test.
For production systems, the chassis can be supplied fully assembled, wired, and tested. That configuration can reduce the number of mechanical and electrical integration steps remaining at the customer’s system level. It also supports a documented configuration in which the chassis, backplane, power subsystem, wiring, and installed hardware are treated as one controlled assembly.
Power supply and redundancy options
The Series 2270 supports plug-in power supplies in either 3U or 6U x 8HP x 160 mm formats, using PICMG 2.11 Revision 1.0 power-supply specifications.
Power can be provided by one, two, or three plug-in power-supply modules. The available configurations support two different design objectives:
- Total power capacity: Multiple modules can be used to provide the required system load capacity.
- N+1 redundancy: An additional module can provide redundancy for hot-swap applications, allowing the system to continue operating after the loss or removal of one supply, subject to the system load and selected power architecture.
Power sizing should include the maximum load of all installed cards, transition modules, cooling fans, storage devices, and other chassis hardware. Startup current, transient demand, power sequencing, and allowable derating should also be evaluated before selecting the module quantity.
The Series 2270 product family includes a related plug-in power supply option, while the broader Vector backplane portfolio supports system-specific interconnect and power-distribution requirements.
Monitoring and custom configuration
The standard Series 2270 architecture can be adapted for application-specific requirements. Documented custom options include:
- Custom backplane design
- Alternate power-supply configurations
- Mechanical modifications
- Local system-voltage monitoring through LEDs
- Remote monitoring through RJ-45 or RS-485
Monitoring provisions should be defined according to the maintenance and control architecture of the finished system. Local LED indication can support bench inspection and service procedures. Remote monitoring through RJ-45 or RS-485 can allow voltage-status information to be incorporated into a broader equipment-control or diagnostic system.
Custom mechanical work should be evaluated with the same discipline as the baseline chassis. Changes to panels, cutouts, card guides, cable access, fan openings, or internal supports can affect airflow, electromagnetic compatibility, structural stiffness, service access, and manufacturability.
Design considerations for engineers
The Series 2270 is best understood as a compact horizontal-card system platform rather than simply a rack enclosure. Its design decisions are interconnected:
- The 1U–4U height range controls available card and power volume.
- The 6U x 160 mm front cage supports primary board installation.
- The 6U x 80 mm rear cage provides a defined location for transition modules.
- The VME, VME64x, cPCI, and VPX backplane compatibility supports multiple system architectures.
- The left-to-right push-pull airflow path establishes the rack-level thermal interface.
- The PICMG 2.11 plug-in power options support modular power distribution and N+1 configurations.
- The monitoring and mechanical customization options allow the enclosure to be adapted to a controlled system configuration.
The resulting design is appropriate where card-based electronics require compact rack density, rear I/O access, controlled side-to-side cooling, and a defined mechanical interface. The critical engineering task is not selecting a nominal chassis height in isolation; it is validating the complete card, backplane, power, airflow, cabling, and service-access stack-up before the system enters production.
A compact enclosure is effective when its mechanical density does not compromise thermal margin, maintainability, or configuration control. For horizontal 6U card systems, those requirements must be resolved together.
Related Vector resources: Series 2270 product page · Chassis and system enclosures · Backplanes · Plug-in power supplies