By Bruce M. Berman – ComNet Vice President of New Business Development The industrial security market has been witnessing the gradual transition to video, audio, and data transmission over Ethernet since the beginning of this decade. This change has impacted numerous other markets as well, including the transportation, factory automation/ industrial control, and utility/ electric power transmission and distribution markets. Prior to the introduction of video over IP (or Internet Protocol), a separate network of analog or digitally encoded video was typically utilized for hauling the video from the edge of the network back to the monitoring location. Audio for telephony or a communications intercom system; RS-232, RS-422, or RS-485 serial data, commonly used for CCTV camera pan-tilt-zoom (PTZ) control or the card access element of the system, was transmitted from the field devices back to the control center on other dedicated and parallel networks (see figure 1). The transmission media of choice was usually optical fiber for reasons of robustness and bandwidth. These technologies and system design approaches are still very viable solutions for hauling high-quality full-motion video, audio, and data, and when optical fiber is employed as the communications media, extremely long transmission distances and electrically noisy environments are easily accommodated. The difficulty of installing and maintaining two or more parallel and technically diverse networks, one for video, one for audio, and another for serial or other data, has motivated many users to consider the use of Ethernet as their preferred communications networking system. The relative ease of integration of the key components of the system onto a common platform has largely made Ethernet the networking solution of choice in many markets, including the industrial security market. With the advent of Ethernet, it now became practical and cost-effective to consolidate the video, audio and data elements of a security communications subsystem onto a single network (see figure 2). Although in theory this should be the ideal platform for the typical local or wide area communications network utilized for industrial security and other surveillance applications, in practice several key and recurring issues are frequently encountered by the systems integrator and end-user responsible for the installation, maintenance, and operation of the system. When analog video is to be deployed onto the network, a video encoder is required to convert the camera video output into an electrical signal that is compatible with transmission over an Ethernet-based network. These encoders employ signal compression technology to reduce the bandwidth occupied by the video, so as to increase the number of potential video, audio, or data signals that may share the finite bandwidth available on the network. Present video compression standards include MPEG-2, MPEG-4 and H.264, with MPEG-4 currently most widely used. The H.264 standard is newer and offers the advantage of enhanced video quality with the benefit of reduced bandwidth. MPEG-2 was originally developed for use by the commercial television broadcast industry, and although capable of superb video quality, its bandwidth requirements are large. As such, it has not been widely accepted for use within those communications networks employing Ethernet. Regardless of the compression standard utilized, hardware decoders or decoding software compatible with the encoded video are required for viewing the video. One major issue involves the relative lack of MPEG-4 or H.264 video encoders that are environmentally hardened when these devices are installed in an out-of-plant operating environment. In this kind of environment, issues such as ambient operating temperature, voltage transient protection, vibration, mechanical shock, and humidity with condensation must be considered to ensure that the video encoders or other field equipment are capable of providing long-term reliability and stable performance. The market is full of suppliers that build quality encoders designed for deployment in benign, conditioned operating environments such as when the equipment is fielded in an adequately heated and cooled communications equipment room. However, those manufacturers that build hardware capable of withstanding the extended operating temperature range, humidity with condensation, and electrical voltage transients and noise encountered in an outdoor or out-of-plant environment are few and far between, and the equipment is costly as a result. The MPEG-4 and H.264 video compression standards are suitable for transmission over Ethernet. As these standards rely upon video compression, the video in these standards is not transmitted in real time, and exhibits a certain amount of latency depending upon the compression standard utilized. Some users may encounter potential legal issues with video transmission systems that are not real-time. Other users may have operator issues with the time lag or delay between executing a pan-tilt-zoom command, and the actual execution of the command as viewed on the CCTV monitor. Full-motion 30 frames per second true broadcast-quality video with zero latency is not achievable considering the current state of Ethernet-based systems, and significant system bandwidth is required to achieve acceptable video quality. The high system bandwidth requirement imposed by the video ultimately limits the total number of video channels and other signal sources that may be inserted onto the Ethernet platform. Many end-users have been disappointed with the video quality of their video-over-Ethernet system, especially when the video is viewed on highly revealing wall monitors. In addition, some video surveillance or monitoring applications mandate the use of high resolution cameras, and much of the resolution provided by these cameras may be lost when the video is compressed to MPEG-4 or H.264 and inserted onto the network. Although Ethernet is based upon the industry accepted IEEE 802.3 standard, and in theory any manufacturer’s Ethernet equipment should be completely interoperable with any other manufacturer’s equipment, in practice this is very frequently not the case. Interoperability issues require the involvement of a trained IT professional to resolve, and in some cases, resolution is not possible. Trained IT or technical personnel are required for the initial installation, setup, and long-term maintenance of the system, and the long-term cost associated with this are obvious and frequently not within the budget of many users. They must be considered as part of the overall life-cycle cost of owning and operating the…