What Is a Backplane?
A backplane is a circuit board used in electronic equipment such as computers and telecommunications equipment to connect boards and cards.
It is typically mounted on the back of a device to transmit power and signals to inserted cards and modules. A backplane also consists of brackets for securing boards, sockets for supplying power, and connectors for transmitting signals.
Backplanes are essential to the performance of electronic devices. They support the board, reduce the effects of board vibration and heat, and improve reliability.
Uses of Backplanes
1. Servers and Network Equipment
Backplanes are used in hardware such as servers, network switches, and routers. These devices require many components to process data in parallel at high speed. The backplane efficiently transfers data between these components to maximize system performance.
2. Data Storage System
Backplanes are commonly used in data storage systems to process and store large amounts of data at high speed. These include RAID arrays and storage area networks (SANs).
3. Industrial Computers
Backplanes are also common in computer systems used in manufacturing, energy, transportation, and other industries. Ruggedness and reliability are important in these systems, and backplanes are used to meet these requirements.
4. Test Equipment
Test equipment is used to measure the performance and quality of electronic equipment. Test equipment uses backplanes to connect multiple test cards to accommodate a wide variety of measurement items and conditions.
Principle of Backplanes
To understand the basic workings of a backplane, it is important to understand how it connects hardware components and transfers data.
1. Component Connections
A backplane essentially consists of one or more printed circuit boards. These boards are equipped with slots or ports for connecting the various components of a computer system.
These slots essentially correspond to a specific type of component (e.g., CPU, RAM, hard drive, etc.). Components are physically connected to these slots and communicate with other components through the backplane.
2. Data Transfer
One of the primary functions of a backplane is to allow data transfer between components. This is done through electronic circuits located on the board. Each component uses these circuits to send and receive data.
Depending on the backplane design and component type, data can be transferred in parallel (multiple bits are transferred simultaneously) or in serial (one bit at a time).
3. Plug and Play
Some backplanes offer plug-and-play capability to facilitate the addition or replacement of components. This means that a new component can simply be physically plugged into a slot and the system will automatically recognize its presence and enable it to operate properly.
Together, backplanes allow the components of a system to work together efficiently and share data. Backplanes are critical to the performance and scalability of a computer system.
Types of Backplanes
Backplanes come in a variety of standards and forms.
1. Classification by Standard
Backplane standards include PICMG, ISA, PCI, among others. PICMG is a standard developed by the PCI Industrial Computer Manufacturers Group that supports PCI and PCI Express. ISA (Industry Standard Architecture) is a standard which was adopted for early IBM PCs and other products.
PCI (Peripheral Component Interconnect) is the standard which enables high-speed data transfer.
These standards are sometimes, but not always, compatible. The backplane and the cards or boards to be connected must support the same standard.
2. Classification by Form
There are two forms of backplanes: active and passive. Active backplanes contain chips that buffer signals between slots and can accommodate complex systems.
Passive backplanes do not have any features that drive the circuitry, but have arbitration circuitry on the card or board side. Active backplanes are more likely to fail than passive backplanes.