The PCI Industrial Computers Manufacturer's Group is a consortium of over 300 industrial computer product vendors. PICMG's charter is to develop specifications for PCI-based systems and boards for use in industrial computing applications. Membership in PICMG is open to any organization or individual with a legitimate interest in helping to extend the PCI standard in the industrial marketplace.
A printed circuit board with slots into which other cards are plugged into, Active backplanes contain, in addition to the sockets, logical circuitry that performs computing functions. In contrast, passive backplanes contain almost no computing circuitry.
The Base interface comprised of a single row of signal pins for a total of four signal pairs per Base interface. In total the Base interface contains up to 14 Base channels for a total of 56 possible signal pairs per board/slot. A Base channel can be used to support a 10/100/1000BASE-T Port comprised of four signal pairs.
A Fabric Channel is comprised of two rows of signal pairs for a total of eight signal pairs per Channel. Thus, each connector supports up to five Channels available for Board to Board connectivity. A Channel may also be viewed as being comprised of four 2-pair Ports.
The update channels are backplane connections between pairs of front cards that operate on a redundant basis . Application software can use the update channel for redundancy interlock, or to provide a direct connection that bypasses the (indirect)fabric interface.
Differential mode signals propagate through a pair of traces. One trace carries the signal while the other carries the opposite-amplitude signal.
Dual Star Topology Backplanes require two dedicated Slots (Hub Slots) for Hub Boards to be inserted. These Slots are Logical Slots 1 and 2. Each Hub Slot has a Channel connection to each Node Slot in the Backplane. The two Hub Slots are also connected to each other in the Backplane by one Channel. Channel 1 of the Node Slots is always connected to the Hub Slot, which is Logical Slot 1, while Channel 2 of the Node Slots is always connected to the Hub Slot, which is Logical Slot 2. The number of Slots supported within a particular Dual Star Backplane implementation may vary up to a maximum of 14 total Node Slots that are connected to two dedicated Hub Slots (having a total of 16 Slots). In a similar manner as a Dual Star Backplane, a Dual-Dual Star Backplane is capable of supporting two distinct and redundant switching fabrics across the Backplane. Applications may benefit from utilizing distinct Fabric Interfaces for unique purposes, and a Dual-Dual Star is a prominent system topology for implementing such an architecture. This is a defined Backplane and/or system configuration for the Fabric Interface. In a Dual-Dual Star topology each Node Board has four Channels connected to two sets of redundant Hub Boards. The second set of Hub Boards, installed in Logical Slots 3 and 4, serve Channels 3 and 4 of Fabric Interfaces of the Node Boards.
Mesh is an architecture in which each slot is capable of reaching any other slot direct data path (i.e., Channel) to/from each Board in the system to other boards. In the full mesh topology, each node is connected directly to each of the others .Multiple redundant connections among Boards enable highly reliable systems with graceful degradation fault tolerance. Mesh configurations do not utilize a central switch fabric; all Slots can be used for data forwarding and processing resources, which makes maximum use of the physical system capacity. Another advantage of the Full Mesh topology is reduced startup cost for partially equipped system, Backplanes that replicate the connection pattern shall replicate the interconnect pattern modulo n–1 (where n is the number of Slots) for as many full combinations as the 15 Channels permit.
NEBS (Network Equipment-Building System) describe the environment of a typical United States RBOC Central Office. NEBS is the most common set of safety, spatial and environmental design guidelines applied to telecommunications equipment in the United States. NEBS was developed by Bell Labs in the 1970s to standardize equipment that would be installed in a central office. The objective was to make it easier for a vendor to design equipment compatible with a typical Regional Bell Operating Company (RBOC) central office (CO). This would result in lower development costs and ease the equipment's introduction into the network. Telcordia now manages the NEBS specifications.  "NEBS Level 1" means a very low threshold of equipment hazards and network degradation. NEBS Level 1 addresses the personnel and equipment safety requirements of GR-63-CORE and GR-1089-CORE. Operability requirements are not enforced for NEBS Level 1 certification. It is primarily used for getting prototypes into a lab trial. RBOCS require all equipment deployed by telecommunications provider company (sometimes called a "carrier") to be NEBS Level 1 certified. "NEBS Level 2" addresses equipment operability in a controlled environment (usually datacenters) that will not be subjected to environmental stress. Due to ambiguity, this level of certification is rarely (if ever) used. "NEBS Level 3" means the equipment meets all of the requirements of GR-63-CORE and GR-1089-CORE. NEBS Level 3 has strict specifications for fire suppression, thermal margin testing, vibration resistance (earthquakes), airflow patterns, acoustic limits, failover and partial operational requirements (such as chassis fan failures), failure severity levels, RF emissions and tolerances, and testing/certification requirements.
ATCA stands for - Advanced Telecom Computing Architecture (also called AdvancedTCA), it is a new series of PICMG specifications targeted to requirements for the next generation of carrier-grade communications equipment.
The AdvancedMC (Advanced Mezzanine Card) standard, defines the base level requirements for a wide range of high speed mezzanine cards, optimized for, but not limited to, AdvancedTCA and MicroTCA carrier blades.
MicroTCA (Micro Telecommunications Computing Architecture) is complementary to ATCA, but is optimized for smaller scale and more price sensitive applications. The basic premise of MicroTCA is to support mezzanine boards, conform to the AdvancedMC standard and connect them directly to the backplane.
PEM stands for Power Entry Module , it is the power feeding component for the chassis in the ATCA , μTCA , CompactPCI etc' ,it's intend to regulate the power to the chassis and prevent current surges from interrupting to the normal operation of the shelf.
RAS stands for reliability, availability, and serviceability which are the base foundation upon Asis obligation to all the clients.
A Field Replaceable Unit (FRU) is a part that can be quickly and easily removed from a piece of electronic equipment and replaced by the user without having to send the entire product to a repair facility.
The European Telecommunications Standards Institute (ETSI) is an independent, non-profit, standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection.
Cubic feet per minute (CFM) is a non- International System of Units, of measurement of gasflow (most often airflow) that indicates how many cubic feet of gas (most often air) pass by a stationary point in one minute. In other words, it is a unit for measuring the rate of flow of a gas or air volume into or out of a space.
The Restriction of Hazardous Substances Directive (RoHS) 2002/95/EC was adopted in February 2003 by the European Union. The RoHS directive took effect on July 1, 2006. This directive restricts the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment. It is closely linked with the Waste Electrical and Electronic Equipment Directive (WEEE) 2002/96/EC which sets collection, recycling and recovery targets for electrical goods and is part of a legislative initiative to solve the problem of huge amounts of toxic e-waste.
SHMM stands for shelf manager module.  It is the component that is in charge of controlling the shelf on all of its elements such as fan trays and power supplies. It also provides the external connectivity from a monitoring application to the shelf through serial link or Ethernet link.
RTM stands for Rear Transition Module, some times it is referred also as Rear I/O.
PMC (PCI Mezzanine Card) - a mezzanine bus based on the well established high performance PCI (Peripheral Component Interconnect) specification.
In telecommunication, an eye pattern, also known as an eye diagram is an oscilloscope display in which a digital data signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep. It is so called because, for several types of coding, the pattern looks like a series of eyes between a pair of rails , the term eye pattern is very common in the signal integrity field.
MTBF - Mean Time Between Failures, MTBF, and MTTR, Mean Time To Repair are basic measures of reliability. MTBF is usually calculated and means the number of hours that pass before the first failure of a piece of equipment.  MTTR is an estimated value of the time it takes to repair a system.
ATCA is focused on the needs of next- generation communications equipment. The architecture is optimized around connectivity requirements of signaling and media gateways, while also providing headroom for higher performance computing elements. ATCA offers a scalable backplane environment that supports: 1. A variety of standard and proprietary fabric interfaces 2. Robust system management 3. Superior power and cooling capabilities.
In telecom applications, ATCA shelves are typically stacked in a NEBS/ETSI rack, which provides redundant - 48 Vdc feeds from separate battery sources to each shelf. The rack may also provide 110/220 Vac power conversion to support a non telecom environment. Each shelf distributes this redundant power across the backplane to individual blades. Isolating dc/dc converters on each blade convert the -48 Vdc feeds to the dc voltages needed to supply on-board logic. When an ATCA board is inserted into a live slot, the shelf provides partial power (payload power disabled) to the board's IPMI interface, which uses a redundant I2Cbased intelligent peripheral management bus physical interface that is also wired into the ATCA shelf. The shelf manager interrogates the blade to determine whether its switched fabric interface is compatible with the rest of the shelf and how much power the board needs. The shelf manager then enables payload power to the ATCA front board, which in turn supplies it to the rear transition module (if present). The power-up process is identical for attached AMC modules.
It is the intent of PICMG 3.x family to accommodate a wide variety of switch fabrics in a layered set of specifications that evolves over time along side the evolution of fabric technologies. Following is the current plan for ATCA Spec layering: PICMG 3.0 Core specification - defining architecture mechanicals, power, system management, and fabric connectors PICMG 3.1 Specification for Ethernet and Fibre Channel fabric interconnects PICMG 3.2 Specification for InfiniBand® Fabric interconnects PICMG 3.3 Specification for StarFabric** interconnects PICMG 3.4 Specification for PCI Express* fabric interconnects PICMG 3.5 Specification for Rapid I/O.
IPMI – Intelligent Platform Management Interface, defines a standardized, abstracted, message-based interface for intelligent platform management hardware. IPMI also defines standardized records for describing platform management devices and their characteristics. IPMI increases reliability of systems by monitoring parameters such as temperatures, voltages, fans and chassis intrusion. IPMI provides general system management functions such as automatic alerting, automatic system shutdown and re-start, remote re-start and power control. The standardized interface to intelligent platform management hardware aids in prediction and early monitoring of hardware failures as well as diagnosis of hardware problems.