A few days ago, I saw discussions in my technical group about the topic of “TTL, RS232, and RS485 transmission distances“. Today, I took some time to share relevant content. Overview Many readers might not know what TTL, RS232, and RS485 are, so this section provides a brief overview of them. 1. TTL Level TTL: … Read more
Follow the IoT Planet to track the latest developments in the Internet of Things! “IoT Planet” focuses on sharing technologies and applications related to the Internet of Things. In the Internet of Things, communication lines are used to transmit data, signals, and power to establish communication links between devices. Common communication lines include USB cables, … Read more
1. Review: Overview of ROS Communication Mechanism & Similarities and Differences with MQTT Communication Overview of ROS Communication Mechanism The main communication mechanisms in ROS are as follows: 1. Topics ○ Publish/Subscribe Model: In this communication method, nodes can publish messages to a topic or subscribe to a topic to receive messages. This method is … Read more
Data packets sent by IoT smart devices must be encapsulated by the corresponding protocol at each layer. With the rapid development of Internet of Things (IoT) technology, most smart devices’ communication modules support various network communication protocols such as TCP, UDP, MQTT, CoAP, HTTP, and LwM2M, which include both transport layer and application layer protocols, … Read more
MQTT Packet Structure In the MQTT protocol, an MQTT packet consists of three parts: Fixed Header, Variable Header, and Payload. (1) Fixed Header. Present in all MQTT packets, indicating the packet type and group class identifier. (2) Variable Header. Present in some MQTT packets, the packet type determines whether the variable header exists and its … Read more
What is a Communication Network There is a network surrounding us at all times, such as telephone networks, telegraph networks, television networks, computer networks, etc.; even within our bodies, there are many network systems, such as the nervous system and the digestive system. The most typical example is the computer network, which is a combination … Read more
I remember the first time I learned about the global Internet, I wondered what it was really like. When people told me there was a computer network covering almost all of the United States and many places around the world, the first image that came to my mind was a thick cable running along telephone … Read more
Source: https://juejin.cn/user/3931509313252552/postse In communication and IT work, networking is essential, and the most important protocol in the network is TCP. Whether in actual work or in written exams and interviews, you can’t escape TCP. I have read documents related to TCP in the RFC, examined the source code related to TCP in Linux, and looked … Read more
Introduction: In actual work environments, PLCs may communicate and exchange data. Typically, communication requires devices to be on the same network segment. However, what if our devices are not on the same segment? This article introduces how two PLCs can perform TCP/IP communication to exchange data when they are not on the same network segment. … Read more
What Is a Communication Network There is always a network around us, such as telephone networks, telegraph networks, television networks, computer networks, etc.; even within our bodies, there are many network systems, such as the nervous system and the digestive system. The most typical representative is the computer network, which is a combination of computer … Read more