By Dan Payerle Barrera
Applying Network Testing Practices to Closed-circuit Television
Testing and documentation of low voltage and fiber optic communications cabling has been standard practice since the introduction of multi-function LAN cable certifiers in the early 1990s. LAN cable certifiers perform a variety of tests that ensure the installed systems meet industry standards and generate detailed reports that serve multiple purposes.
Test reports provide assurance to the network owner that their new network infrastructure provides the performance they paid for. Reports can be submitted to the manufacturer of the cabling system to activate warranty programs that cover material and labor defects. In addition, the reports protect the installation contractor by providing proof of “as-built” performance, meaning call-backs can be billed as service calls instead of free warranty work.
However, the concept of documenting closed-circuit television (CCTV) installations, which have become increasingly common in the utilities sector, to provide this same level of protection to integrators and installers is very new. Until recently, test tools that allow professional reporting of CCTV installations did not exist, meaning installers are routinely called back to troubleshoot problems that may be caused by the customer’s network and not the CCTV system.
What to Test and What it Means
All new CCTV systems installed for safety and security in the utilities sector are digital/IP, running over Ethernet cabling and have many advantages over analog/coaxial systems. However, one particular disadvantage of IP CCTV is that video quality is affected by network performance. Ideally an IP CCTV system should be on its own separate network, but, in reality, many businesses insist CCTV and business systems run on the same network to reduce costs. As a result, network congestion and bandwidth limitations of the customer’s network may result in poor CCTV performance with symptoms that include:
• Reduced video frame rates—choppy video where moving objects jump across the screen;
• Higher video compression—reduced image clarity, high pixilation of video; and
• Network buffering—video pauses and hesitates, then catches up and hesitates again in a continuously repeating cycle.
When any of the previous symptoms occur, it often will be assumed that the fault is with the CCTV system, putting the integrator in a position of troubleshooting the client’s network or trying to prove the CCTV system is being affected by external conditions.
Documenting the CCTV system before turning it over to the client gives integrators/installers proof of performance that the cameras are performing as expected after installation. The equipment used to test and document a CCTV system will capture network and video information to provide a snapshot of each camera’s configuration.
FIGURE 1: CCTV Installation Report
The key data recorded to generate a CCTV test report are:
• Camera IP address—the network address of the camera and whether it is fixed (static) or assigned by the network (dynamic). The IP address is programmed during installation.
• Network details—complete network configuration of the camera including gateway, DNS, subnet and other information to ensure the camera is connected to the intended network.
• Camera MAC address—the unique hardware ID of the camera which is often the serial number. The MAC address cannot be changed.
• Location of the camera—a description of where the camera is installed and what it is aimed at.
• Screen capture—a picture of what the camera is monitoring. The screen capture is key because it shows the camera’s field of view and that it is properly focused. Reports should allow multiple images to demonstrate both day and night image quality.
• Video resolution—the resolution of the video stream, ex., 1920 x 1080 is “full HD.” This proves the camera is filming at the resolution required by the client.
• Frame rate—number of images captured per second (fps). Most cameras will allow up to 25-30 fps for smooth video. The frame rate can be reduced to lessen the impact on network bandwidth.
• Video CODEC—the type of compression used to stream video. Common types are H.264 and MJPG. The CODEC used affects video quality and bandwidth.
• Bandwidth—the average amount of data streaming from the camera at the current video configuration settings, measured in megabits per second (Mb/s). Bandwidth is a function of resolution, frame rate and CODEC.
Reduce Maintenance and Repair Time
The benefits of having installation documentation extend beyond closing out the project with test reports. If a camera needs to be replaced at a later time, for example, the replacement should be configured just like the failed camera to ensure the system can return to normal operation as quickly as possible. If the necessary information is available from reports, this process can be streamlined and reduce downtime.
In practice, this means that at the office, the report for the failed camera can be retrieved and used as a template for the replacement. The report contains the camera brand and model, allowing the correct replacement to be pulled from inventory. While at the office, the new camera can be programmed with the network settings, location, description and video settings that were captured on the original report.
A technician can then take the pre-configured camera to the site, swap it out and use the field tester to create a new report. The updated report can be compared to the original to verify the field of view and video setting are the same as the original. Time on site and labor costs for service calls can be significantly reduced when technicians and service personnel are armed with the information and tools to maximize efficiency.
FIGURE 2: Multi-function CCTV installation and test tool
More than Documentation
Documentation is just one function of multi-function CCTV testers. They also provide field technicians with tools to troubleshoot cable and network problems, test PoE (Power over Ethernet), test video monitors, and much more. And while IP is here to stay, the installed base of analog cameras as well as new HD coax systems must also be supported. CCTV testers that support IP, analog and HD coax cameras, plus cable and network troubleshooting minimize the equipment technicians need to carry to the utility job site. They can also replace laptops, PoE injectors and other cumbersome devices that are difficult or even dangerous to use while on a ladder or lift.
The new generation of CCTV testers improve productivity, profitability and safety while making it easy for technicians to migrate from analog to network/IP installations.
About the author: Dan Payerle Barrera is global product manager for IDEAL Networks. For more information, please visit www.idealnetworks.net.