Especially when the transmission is carried over a long wire outdoor, the wires is potential to carry the dangerous signal like lightning or other high voltage induction. Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. It requires minimal wiring and can share the wiring among several seats, reducing weight. RS485 cable length can be as long as 1.2 km, while RS232 only about 25 meters. As a rule of thumb, the speed in bit/s multiplied by the length in metres should not exceed 108. Thus a 50-meter cable should not signal faster than 2 Mbit/s. Using a repeater, the main cable is divided into different segments, each of which can be up to 700 m in length and connect 32 devices (this number includes the repeaters). You can easily connect more devices by splitting the cable at one connector and adding another cable to it.

For RS232 a crossover cable is used where pin 1 is connected with pin 6 at the other connector, pin 2 with pin 5, etc. This interconnects the transmit and receive signals of both PLCs, and also the handshaking signals DTR and DSR. The A signals of all devices should be connected with each other and the same goes for the B signals. These signals are commonly called A and B in RS485 systems. Electrical signaling is balanced, and multipoint systems are supported. RS-485, also known as TIA-485(-A) or EIA-485, is a standard, originally introduced in 1983, defining the electrical characteristics of drivers and receivers for use in serial communications systems. 3106A is what I typically use to wire balanced audio. RS-485 serves as a physical layer for the AES3 digital audio interconnect. Although many applications use RS-485 signal levels, the speed, format, and protocol of the data transmission are not specified by RS-485. DH 485 is a proprietary communications protocol used by Allen-Bradley in their line of industrial control units. It is also used in Digital Command Control (DCC) for model railways.

With one sing coaxial cable, both the video data transmission and PTZ Control are achievable. This shields the inner data wires from external interference. RS-485, like RS-422, can be made full-duplex by using four wires. The probe can be cut to any length from 150mm to 300mm. An RS485 interface with a definable address allows it to be used directly on a modbus network. Utilizing a series of dedicated interface devices, it allows PCs and industrial controllers to communicate. Our plans to upgrade our solar PV system this year are slowly progressing with installing a new Solis 1.5kW inverter and an EM112 Series Energy Meter, which have RS485 output and communicate using Modbus protocol. The probes communicate using the standard Modbus RTU protocol. The EIA once labeled all its standards with the prefix "RS" (Recommended Standard), but the EIA-TIA officially replaced "RS" with "EIA/TIA" to help identify the origin of its standards. 12 V, i.e. ±7 V on top of the 0-5 V signal range. To minimise shadows over the top row of panels, we decided to mount 2 on the top row and 3 below, which will give us a theoretical maximum output of 1.6kW, which is suitable for the Solis Solar 1.5kW Mini 5G Inverter.

It has an EM112 Series Energy Meter fitted in the same box to monitor energy production and consumption of the inverter. RS485 uses two wires and sometimes a ground connection, so we used a twin-screen cable to go between the inverter to the EM112 Series Energy Meter and then onto the Raspberry Pi with a DB9 connector connected to the RS485 Pi board. Removing the WiFi adapter and connecting directly to the inverter's COM port resulted in no data again so we knew that there was something on the WiFi adapter enabling the data from the inverter. RS-485 is used for low-speed data communications in commercial aircraft cabins' vehicle bus. Bus Probes can be configured and tested using our web-based test app (you will need to connect the probes to your PC or Android smartphone via our Web485 board). This connection may be used to limit the common-mode signal that can be impressed on the receiver inputs.