Twisted pair also allows the transmission speeds to be much higher than what is possible with straight cables. It then pumps out the bytes pretty much in a similar fashion, grouped per "frame". For example, at 4800 baud (bits per second), each bit lasts about 200 microseconds (µs), and if communications are full duplex (e.g., if the QScreen Controller echoes each incoming character), then there is a serial interrupt every 100 µs or so. For example, Belden 3105A cable can be specified, but different types of cable with equivalent characteristics can be used. At 1200m of transmission speed, you can use only 100kbps of transmission speed. The QED-Forth kernel includes pre-coded drivers that configure and control the SPI for maximum speed data transfers. Its speed is strictly defined at 250kBaud. No device bearing the DMX mark may use any other speed. UART is an Asynchronous transmission device hence there is no clock signal to sync the data between the two devices instead it uses start and stop bits at the start and end of each data packet respectively to mark the extremities of the data being transferred.

We have been using Microcontroller Development Boards like Arduino, Raspberry Pi, NodeMCU, ESP8266, MSP430, etc. for a long time now in our small projects where most of the times distance between the sensors and board is not more than few centimeters at max and at these distances, the communication between the different sensor modules, relays, actuators, and controllers can be easily done over simple jumper wires without us being worried about the signal distortion in the medium and the Electrical noises creeping into it. It’s important to note that all devices on the network need to use the same logic for interpreting voltage differences as bits (i.e., whether A being at a higher voltage than B represents a ‘1’ or a ‘0’).In a network with multiple devices, each device needs to have a unique address so that it knows when to listen and when to ignore the communications on the line. You can use the QScreen’s RS485 link to create such a multi-drop serial network. It can only transmit/receive data serially, so it first converts the parallel data into serial data and then transmits the data. On the other hand, DMX chose a nice round number at what was then the top of the range and added protections to avoid pick up of "ridiculous" frequencies, what is rs485 cable that we would now consider for actual data.

The DMX standard uses that RS485 (or, for clarity RS422 would be better) standard for its hardware medium description, but that's where it ends. RS-485 standard conformant drivers provide a differential output of a minimum 1.5 V across a 54-Ω load, whereas standard conformant receivers detect a differential input down to 200 mV. It operates on a differential signaling method of measurement rather than voltage measurement wrt GND pin. To reduce the effect of interference from external electrical signals the RS485 interface uses a differential signal over a "twisted pair" cable. 7) has the same effect. In order to avoid errors when many devices are connected, cables of the same colour should be used for all the connections to the terminals A and cables of the same colour should be used for all the connections to the terminals B of the various devices (e.g. white for A and blue for B).

In some countries, inserting two cables into the same screw terminal is permitted. In this tutorial, we are going to learn about the RS485 communication protocol and how to implement it with the two Arduino Nano we have with us and how to use the MAX485 RS485 to UART conversion Module. There are many categories of Ethernet cables we can use like CAT-4, CAT-5, CAT-5E, CAT-6, CAT-6A, etc. In our tutorial, we are going to use CAT-6E cable which has 4 twisted pairs of 24AWG wires and can support up to 600MHz. It is terminated at both ends by an RJ45 connector. In order to increase the extent of the Modbus network, repeaters can be used; and signal amplifying and regenerating devices provided with two communication ports that transfer to each what they receive from the other. In order to avoid signal reflections, a 120 Ohm termination resistance must be fitted on each end of the main cable.