Rc 5 Remote Control Views

Electronics

Also, the decoder functionality will often be integrated into a more complicated micro-controller that controls the A/V device, eliminating the need for the separate chip. In the absence of a viable standard, the microcontrollers can be used to emulate the ambiguous protocols used by the old dedicated encoder/decoder chips and it appears that this is often the case. There are even stripped down 4 bit mask programmable microcontrollers designed only for remote control use (such as NEC uPD6124A (discontinued), uPD6125A (discontinued), uPD6126A (discontinued), uPD6132, uPD6133, uPD6134, µPD1724x, uPD67AMC, uPD68AMC, uPD68AMC, uPD6P9M1MC (OTP), upd6PLM3MC (OTP), and µPD17932x (8-bit)). These offer keyboard wake, low power standby modes, and sample controller code though similar features are present on more general PIC microcontrollers or Atmel AVRs.

Sony manufactured a number of consumer devices of different types that share a common protocol, called S-link. A jack on each device allowed the remote control signals to be interconnected between devices. The protocol included the useful but unusual feature of supporting more than one of the same type of device (such as multiple CD changers). Some A/V components could generate informational status codes that could be used to do things like automatically stop your tape deck when the CD you were recording stopped playing. Software running on a PC with a suitable interface could also control the A/V components and monitor their activity; for example, your computer could tell what disk and track were playing in your CD changer and look up the titles in one of the internet CD databases. Sony charges 5000 USD for access to the S-Link documentation[1].

The RC-5 and RECS-80 codes developed by Philips have been casually referred to as international standards [2][3]. However, the RECS-80 protocol was prone to interference and was quickly replaced by the RC-5 protocol. Although it appears that they were proprietary protocols developed by Philips, they were also adopted by various other manufacturers, specifically European- and US-based ones. This allowed interoperability between the remote handsets and equipment of various brands. The RC-5 code was, and still is, used by many US- and European-based manufacturers of specialty audio/video equipment. Unfortunately, documentation of the standard commands were not widely distributed. Therefore, there are some brands of equipment that use non-standard commands, causing interference with other equipment also using the RC-5 protocol.

RECS-80 uses pulse position modulation and RC-5 uses bi-phase. Early dedicated-purpose chips were offered by Philips Semiconductors to allow for the easy use of RECS-80 and RC-5 protocols. The SAA3004, SAA3007, and SAA3008 encoder chips used RECS-80, and the SAA3006 and SAA3010 encoder chips used RC-5. The SAA3049A decoder chip decoded either type. (Note that the Philips Semiconductors division is now NXP). All of these chips have been discontinued. However, these transmission protocols are easily created and/or decoded with general-purpose 8-bit microcontrollers, such as those offered by Microchip Technology and Atmel.