\r\n\t\t\t\tWhat is DTMF?\t\t\t<\/div>\r\n\t\t\t\r\n\t\t<\/div>\r\n\t\t
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Dual-tone multi-frequency<\/p>\n\n\n\n
The tones that are heard when you press the buttons on a touch-tone telephone and allows you to send data via PSTN (analogue telephone line). DTMF assigns a specific frequency (consisting of two separate tones) to each key. This is also the system that most emergency analogue telephones use to transfer information e.g., background call information.<\/p>\n\t\t<\/div>\r\n\t<\/div>\r\n\t\t
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\r\n\t\t\t\tWhat does GSM and DCP mean?\t\t\t<\/div>\r\n\t\t\t\r\n\t\t<\/div>\r\n\t\t
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GSM stands for Global System for Mobile Communication. The DCP stands for Digital Communication Platform and combines the GSM with the lift emergency telephone and machine to machine gateway.<\/h4>\n\n\n\n
The DCP has a power source and one internal battery capable to power a limited number of CAN devices (200mA max). When there are a number of CAN devices connected to the DCP it is necessary to add an additional power supply. As a rule of thumb, when a CAN splitter is needed, an extra power source may be required<\/strong>.<\/p>\n\n\n\n
A GSM unit is voice only, whereas GPRS is voice and data.<\/p>\n\t\t<\/div>\r\n\t<\/div>\r\n\t\t
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\r\n\t\t\t\tWhat is IP?\t\t\t<\/div>\r\n\t\t\t\r\n\t\t<\/div>\r\n\t\t
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Internet Protocol. A packet-based protocol for delivering data across networks.<\/p>\n\t\t<\/div>\r\n\t<\/div>\r\n\t\t
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\r\n\t\t\t\tWhat is CANbus?\t\t\t<\/div>\r\n\t\t\t\r\n\t\t<\/div>\r\n\t\t
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CANbus (Controller Area Network) is a vehicle bus standard designed to allow smart devices (or nodes) to communicate. Designed by Robert Bosch back in the 80\u2019s, it was initially used by car manufacturers.<\/p>\n\n\n\n
The bus is based in a serial transmission (digital data is sent bit by bit over time) using a differential voltage across a single pair of wires.<\/p>\n\n\n\n
To learn more about CANbus, you can read our insights article: What is CANbus?<\/p>\n\n\n\n
CAN does not send large blocks of data point-to-point from node A to node B. CAN network sends many short messages which are broadcast to the entire network.<\/p>\n\n\n\n
All nodes can transmit information to other nodes in the same bus and any node can be transmitter or receiver.<\/p>\n\n\n\n
There are many reasons why we use CANbus at MEMCO by AVIRE:<\/p>\n\n\n\n
\u2022 Low cost: Devices\/nodes communicate via a single CAN interface not through direct analogue signal lines, therefore, reducing wiring errors and cost.<\/p>\n\n\n\n
\u2022 Robust: The system has a robust physical layer, designed for high noise and other challenging environments.<\/p>\n\n\n\n
\u2022 Centralised: The CAN bus system allows for central error diagnosis and configuration across all devices\/nodes<\/p>\n\n\n\n
\u2022 Flexible CAN messages are prioritised via IDs so that the highest priority IDs are non-interrupted.<\/p>\n\n\n\n
There are some inherent limitations with CANbus, and these include the following:<\/p>\n\n\n\n
\u2022 A maximum number of nodes is not specified for the network but typically it supports up to 64 nodes due to electrical loading.<\/p>\n\n\n\n
\u2022 Undesirable interactions between nodes can occur where one node talks and can disturb the other nodes.<\/p>\n\n\n\n
\u2022 The network needs to follow a certain architecture to achieve the best results.<\/p>\n\n\n\n
\u2022 In order to reduce signal integrity issues such as reflections, CAN bus should be properly terminated at both the ends with resistors.<\/p>\n\n\n\n
\u2022 There is also a limitation of speed of data transmission when the distance is increased. At 200mts the speed is limited to 200Kbps.<\/p>\n\t\t<\/div>\r\n\t<\/div>\r\n\t\t
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\r\n\t\t\t\tWhat are the key things to consider in the CANbus architecture?\t\t\t<\/div>\r\n\t\t\t\r\n\t\t<\/div>\r\n\t\t
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There are a couple of key factors you need to consider when using a CANbus protocol to ensure that interference is kept to a minimum.<\/p>\n\n\n\n
\u2022 The endpoints MUST have the termination resistor.<\/p>\n\n\n\n
\u2022 All other devices must be closer than 30cm to the main \u2018BUS\u2019.<\/p>\n\n\n\n