Section 725 consists of four parts. Part I contains general requirements (which we are talking about here), Part II refers to Class 1 circuits (which we will also discuss here), Part III refers to Class 2 circuits, and Part IV contains list requirements. Here are some examples of the three types of circuits: Class 1 and Class 2 circuits installed in ducts or plenums must comply with section 300.22. [section 725.3(c)] Existing infrared remote controls can be used to control PC applications. Any application that supports keyboard shortcuts can be controlled via IR remotes from other home devices (TV, VCR, AC). [ref. needed] This is often used in multimedia applications for PC-based home theater systems. For this to work, you need a device that decodes the data signals from the IR remote control and a PC app that communicates with that device connected to the PC. A connection can be established via a serial interface, USB interface, or motherboard IrDA port. Such devices are commercially available, but can be homemade with low-cost microcontrollers.

[ref. needed] LIRC (Linux IR Remote Control) and WinLIRC (for Windows) are software packages designed to control the PC with TV remote control and can also be used for homebrew remotes with fewer modifications. However, paragraph 725.27(B) amends the above limits by allowing the use of certain types of fastening wires for Class 1 circuits. Again, electricians need to understand that NEC allows these other types if they are listed for such use. The TFN and TFFN types of fastening wires are often used because the insulation corresponds to THHN thermoplastic. Table 402.3 describes these types of ladders with a nylon outer casing similar to the THNN that protects their insulation during installation. Higher voltages and currents are allowed for Class 3 circuits (as opposed to Class 2 circuits). To avoid the risk of electric shock, the wiring must be at least 300 V [725.71(E) and (F)]. Cabling methods that meet this requirement include PLTC cables, Class 3 cables, or one of the permitted substitutions listed in Table 725.61(A), depending on the conditions of use. The Blab-off was a wired remote control developed in 1952 that turned the sound of a television on or off so that viewers could not hear advertisements.

[25] In the 1980s, Apple`s Steve Wozniak founded a company called CL 9. The goal of this company was to develop a remote control capable of operating several electronic devices. The CORE (Controller Of Remote Equipment) unit was introduced in the fall of 1987. The advantage of this remote control was that it could “learn” signals remotely from different devices. It had the ability to perform some or more functions at different times with its built-in clock. It was the first remote control that could be connected to a computer and loaded with updated software code when needed. The CORE unit has never had much of an impact on the market. It was far too heavy to program for the average user, but it received rave reviews from those who could. [ref. needed] These obstacles eventually led to the demise of CL 9, but two of its employees went on to run the company under the Celadon name. It was one of the first computer-controlled learning remotes on the market.

[26] In the late 1930s, several radio manufacturers offered remote controls for some of their high-end models. [8] Most of these were connected to the device, which was controlled by wires, but the Philco Mystery Control (1939) was a battery-powered low-frequency radio transmitter,[9] making it the first wireless remote control for a consumer electronic device. With pulse number modulation, it was also the first digital radio remote control. Remote controls are used in photography, especially for taking long exposure photos. Many action cameras such as the GoPros [31] as well as standard DSLRs, including Sony`s Alpha series [32] have Wi-Fi-based remote control systems. These can often be accessed and even controlled via mobile phones and other mobile devices. [33] The first television remote controls (1956-1977) used ultrasonic sounds. Today`s remote controls are often consumer infrared devices that send pulses of digitally coded infrared radiation to control functions such as power, volume, channels, playback, channel change, heat, fan speed, or other functions that vary from device to device. The remotes of these devices are usually small wireless portable objects with a series of buttons to adjust various parameters such as TV channel, track number and volume. On many devices, the remote contains all the function controls, while the controlled device itself has only a handful of essential primary controls.

The remote control code, and therefore the required remote control device, is usually specific to a product line, but there are universal remotes that emulate the remote control for most major brand devices. Video game consoles did not use wireless controllers until recently, mainly due to the difficulty of playing the game, while the infrared emitter remained pointed at the console. Early wireless controllers were bulky, and when powered by alkaline batteries, they only took a few hours before they needed to be replaced. Some wireless controllers have been manufactured by third parties, in most cases with a wireless connection instead of infrared. Even these were highly inconsistent and, in some cases, had transmission delays, rendering them virtually useless. Some examples are the Double Player for NES, the Master System remote control system and the Wireless Dual Shot for the PlayStation. The NEC has many requirements for Class 1 circuits. You need to know them all in order to be able to diagnose each situation adequately.

Section 725 of the National Electrical Code (NEC) applies to remote control, signalling and power-constrained circuits that are not an integral part of a device or device. These include circuits for intrusion alarms, access control, sound, nurse call, intercoms, some computer networks, some lighting dimming controls, and some low-voltage industrial controls. The impetus for a more complex type of television remote control came in 1973 with the development of the Ceefax teletext service by the BBC. Most commercial remotes at that time had a limited number of functions, sometimes only three: next channel, previous channel, and volume/off. This type of control did not meet the requirements of teletext sets, where pages were marked with three-digit numbers. A remote control that selects teletext pages needs buttons for each digit from zero to nine, as well as other control functions, such as text-to-picture switching and normal TV controls for volume, channel, brightness, color intensity, etc. Early teletext sets used wired remote controls to select pages, but the continued use of the remote control required for teletext soon showed the need for a wireless device. So BBC engineers began discussions with one or two TV manufacturers, which between 1977 and 1978 resulted in early prototypes capable of controlling many more functions.