Intersil's Security Link over Coax (SLOC) Solution


Enables widespread adoption of digital IP video surveillance

Intersil Corporation has introduced an advanced modem solution designed to simultaneously transmit analog CVBS video and digital IP video over a single coaxial cable. The Intersil Techwell SLOC™ (Security Link over Coax) solution uniquely allows modern mega-pixel IP cameras to operate in the existing CCTV coaxial cable infrastructure without the need for new wiring or cable modifications, providing significant cost and resource savings. Video surveillance systems have been moving toward digital and networked IP technologies, which can expand the functions of security surveillance. Major benefits of networked IP surveillance include remote video accessibility via the Internet and mobile devices, high image quality, intelligent video record and search, and system scalability and flexibility. But the IP migration path has not been easy and the volume of the IP camera shipments today, compared with analog CCTV camera shipments, has only reached approximately 10 to 15 percent. Barriers remain for two basic reasons. First, at the front end of the surveillance system, traditional analog CCTV (closed caption) cameras still dominate because the installed base of coaxial cables is established and significant -- there are approximately 400 million coaxial cables installed worldwide that support analog CCTV cameras. Second, conventional IP camera systems operate on Ethernet Cat 5 (also known as twisted pair) cable rather than coax -- and the cabling upgrade process required to support modern digital IP cameras is sufficiently high to impact return on investment.

The embedded analog CVBS video enables latency-free live viewing and controlling of digital IP cameras. Surveillance system manufacturers can now architect an effective hybrid surveillance system that supports latency-free analog CCTV functions as well as networked IP surveillance functions. The solution is comprised of the TW3801, a SLOC-based camera modem PHY device, and the TW3811, a SLOC-based receiver modem PHY device. Based upon Intersil Techwell technology, the combination of TW3801 and TW3811 provides the security surveillance industry with a seamless migration from a traditional analog system to an IP security system. The SLOC technology leverages the installed coaxial cable infrastructure and enables networked IP functions without requiring significant change to either the IP camera design or the DVR (digital video recorder) design.

Both the TW3801 and the TW3811 are highly integrated modem PHY subsystems that include an analog front end (AFE), a digital modem and two Ethernet media independent interfaces (MII). The TW3801 accepts an analog CVBS signal and an Ethernet MII signal and internally combines these signals into one proprietary output signal for transmission over a coaxial cable. The TW3811 accepts a SLOC output signal from a SLOC-based camera modem PHY IC and decodes it into an analog CVBS and an Ethernet MII signal. SLOC provides many system benefits in addition to leveraging the existing installed coaxial cables. It supports latency-free live camera viewing and control, because analog CVBS video removes all latency between the camera and the DVR. The SLOC technology embeds the native analog CVBS video with the digital data in the transmission. Native analog CVBS video can easily be extracted by filtering out the digital data. Therefore, DVR system designers can leverage the SLOC's embedded analog CVBS video to support live display of cameras via conventional CVBS-based approach commonly used in DVR. SLOC enables an easy transition from analog CCTV systems to digital IP surveillance systems, either as an embedded system or external adapter module, leveraging the CVBS signal, Ethernet MII interface, RS-485 interface, and BNC port commonly found in an IP camera. The BNC port is backward compatible to the CVBS format if the SLOC receiver modem PHY is not detected. This is useful when the BNC port is connected to the CVBS monitor during initial camera setup. Likewise, there is minimal change required for incorporating the SLOC receiver modem PHY in the DVR. System manufacturers can use the embedded analog CVBS video for redundant storage in the DVR to improve reliability and availability, especially in the event of network failure. The net result is that customers are provided with the ability to upgrade their existing analog-based system to the highly feature rich IP security system, including latency-free functionality. The Intersil SLOC solution provides high-performance and robust communications between the IP camera and the receiver at coaxial cable lengths of up to 500 meters. Downlink throughput is up to 36Mbps (from camera to receiver); uplink throughput is up to 11Mbps (from receiver to camera). Pricing and Availability Both the TW3801 and the TW3811 are available in engineering samples in the 100-TQFP (12x12mm) package. Mass production samples are slated for Q1, 2011.