CAN bus (Controller Area Network bus), now widely used in the automotive industry, factory machine automation, medical industry, etc… Often you will come across a CAN bus cable and connection.
The underlaying physical signal of the CAN bus is actually the same differential signal on RS485/RS422. CAN bus value-add with the data communication protocol running on the RS485 kind of physical wires.
CAN Bus pin out (for D-sub09 male/female connector, for RJ45 8P8C connector)
There are various cable and connector standard using CAN Bus protocol. Some system uses D-sub09 male/female connector, some uses RJ45 8P8C jack. There are also CAN Bus implemented on XLR 4 pins connector, as well as . Power supply on the CAN Bus system can be 12V/24V. It depends on the system implementing the CAN Bus.
Connector pin out: D-sub09 (male/female)
reserved
CAN-
GND
reserved
CAN-SHIELD
GND
CAN+
reserved
CAN-V+
Connector pin out: RJ45 (8P8C jack)
CAN+
CAN-
GND
reserved
reserved
CAN-SHIELD
GND
CAN-V+
Connector pin out: XLR 4 pins
24V
CAN+
CAN-
GND
Connector pin out: M12 Circular Connector 5 pins
CAN-SHIELD
24V
GND
CAN+
CAN-
Background about CAN Bus
It was initially developed by Bosch in the mid-1980s to address the complex wiring harnesses found in modern vehicles, which were becoming increasingly complex due to the introduction of advance electronic control units (ECUs) and sensors. It is a communication standard designed for the vehicle industry to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer.
The primary goal of the CAN bus was to reduce the amount of wiring needed in vehicles while providing a reliable communication protocol for various vehicle systems, such as engine management, transmission control, anti-lock braking systems (ABS), airbag systems, and more.
Key features of the CAN bus include:
Differential Signaling: CAN bus uses a differential signaling scheme, where data is transmitted as a voltage difference between two wires (CAN-High and CAN-Low). This provides immunity to noise and interference, making CAN bus communication reliable in noisy automotive environments.
Multi-Master: CAN bus allows multiple nodes (ECUs or devices) to transmit and receive data on the bus simultaneously. This is facilitated by a non-destructive arbitration mechanism where messages with higher priority are given precedence on the bus.
Deterministic Communication: CAN bus provides deterministic communication, meaning that messages are transmitted and received with predictable timing. This is essential for real-time control applications in vehicles.
Error Detection and Fault Tolerance: CAN bus incorporates built-in mechanisms for error detection and fault tolerance. Each message sent on the bus includes a cyclic redundancy check (CRC) to detect errors, and the protocol supports error handling mechanisms such as automatic retransmission of corrupted messages.
CAN bus has become the industrial standard for in-vehicle networking due to its reliability, simplicity, and cost-effectiveness. It has been widely adopted across the automotive industry and is also used in various other applications beyond automotive, including industrial automation, medical devices, and more. Over time, the CAN bus standard has evolved, with newer versions introducing enhancements such as higher data rates and improved error handling capabilities.
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The DEX to RS232 cable is often use for connecting between the vending machine peripheral devices. It is also a common cable for connecting your computer to the DEX network on your vending system.
DEX to RS232 cable pin out
Connectors
DEX connector uses a 3 pins 6.35mm stereo jack (or also known as 1/4″ stereo plug). This jack is the same plug that is widely used on cables in the audio industry.
The pin out of a DEX connector: The tip of the jack is receiving the serial communication data, while the middle ring contact is for the transmit. The last big patch ring is common ground reference for the data signal.
The RS232 uses a D-Sub female 9 pins connector. This side can be plugged to the RS232 port of your computer, or can be connected to a RS232-to-USB converter, so that you can get connected to the serial communication data via the USB port instead. RS232 port is kind of rare in modern computers. RS232 to USB is a very common converter that allow us to connect to RS232 devices from our computer these days.
DEX cable and accessories
You can get your DEX connector, DEX harnesses, DEX to RS232 cable and converter from online.
The following are some of the online places where you can get your DEX stuffs.
