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Many installers believe that fiber optics is an expensive and difficult to implement solution and don't think about it as an alternative to copper cables. They avoid to use fiber optics even in situations where application of this transmission medium seems obvious.
The main factors that should prompt the installer to consider the use of fiber optic transmission in a CCTV system:
- long cable runs,
- several or more cables running in parallel,
- narrow cable shaft,
- industrial environment, electromagnetic interference,
- possibility of surges, overvoltages,
- risk of dampness.
If the system is to be flexible (future expansion plans), this solution also seems to be the best choice.
Nobody disputes the very good parameters of optical transmission, which are an order of magnitude beyond those of coaxial or twisted-pair cables, but the mentioned earlier myth of the high costs and installation difficulties hamper the development of this technology in small- and medium-size systems.
Is really the cost of fiber optics in CCTV high?
Let's examine the issue in the case of an outdoor link to a PTZ camera (so, with transmission of control signals).
Connection of a PTZ camera with the use of copper cables
The installation of the 100-meter-long transmission lines between the PTZ camera and the surveillance room with the DVR and system control unit will cost about 150 Euros (gross retail prices). These are the costs of the cables and protectors that should be used on both ends of the lines. By the way, the 100 m distance is the maximum practical limit of sending video over coaxial cable (without additional amplifiers).
The installation costs are estimated for the following components:
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CCTV Cable CAMSET/YAR PE 75-0.59/3.7+2x0.50 (power) M5997_100 |
Fiber optic cable is completely resistant to electromagnetic fields, power surges, interference, noise and crosstalk. Using a fiber optic cable, the installer does not need to apply any additional protectors. The connection of the PTZ camera with the use of fiber optic transmission medium is shown in the diagram below.
Connection of a PTZ camera with the use of fiber optic transmission medium
The same link has been based on a fiber optic cable and optical video converters. Indeed, the cost of the installation is higher (a little above 200 Euros), but there are 3 spare fibers in the cable. When the monitoring system uses only this single fiber, the other fibers can be used for data transmission between the facilities of the company e.g. office and warehouse (Internet, telephone, fire alarm etc).
The installation costs were calculated for:
- fiber optic video converter set ULTIMODE V-021D L2102,
- outdoor multimode fiber optic cable with 4 fibers.
Video converters ULTIMODE V-021 L2102
The presented comparison has been made for the most unfavorable case for using optical fiber (one camera only). With multiple cameras, the cost of fiber optic solution increases slightly only (application of different video converters) and all video channels can be transmitted over the single fiber. The cost of a copper-based solution increases in proportion to the number of cameras (additional cables) and involves extra installation complexity. Due to small size and weight, optical fibers allow much easier and faster installation than coaxial cables. The optical solution can be easily expanded by replacing the active devices without changing the transmission medium. With the use of single-mode fibers, the transmission distance can reach 20 km.
Perhaps the problem lies in the difficulty of installation?
Sometimes the investor leaves no choice - as in the case of the installer who appeared in one of our branches, obligated to install a 350-meter-long fiber optic link. After selecting the appropriate converters, we prepared the suitable optical cable with connectors. The final installation (except laying the cable) took about 5 minutes - just inserting the appropriate connectors and connecting power supply.
In another case the installer himself suggested the client to connect the office and warehouse with an optic backbone - 24-strand fiber optic cable - to fulfill all current and future telecommunications needs of the client. Additionally, he decided to terminate the fiber optic cable with pigtails using mechanical splices ULTIMODE FAST-MS1 L5550.
In the case of fiber optic cables there are several ways of terminating the fibers with optical connectors. The first and easiest one for the installer is to order ready-to-use cable of the suitable length, with pre-installed connectors - directly from the supplier. Unfortunately, it is not always possible to pull the connectors through existing ducts, so other three options may be used:
- fusion splicing,
- mechanical splicing,
- use of quick assembly connectors.
Mechanical splices and quick assembly connectors are suitable for connecting optical lines in similar cases like fusion splices. The elimination of complex and costly process of fusion splicing the fibers or gluing the connectors greatly simplifies and speeds up the installation work. The mechanical splices ULTIMODE FAST-MS1 L5550 have attenuation on a similar level as fusion splices (0.1 dB).
The application of mechanical splices and quick assembly connectors does not require expensive equipment - everything the installer needs to do is to remove the protective fiber coatings, cleave the fiber and insert it into the body of the mechanical splice or fast connector. The installation process itself takes up no more than 30 seconds. Mechanical splices and connectors are reusable - the fiber can be disconnected at any time.
How to select the devices?
The most important parameters that should be taken into account when selecting optical devices and the optical cable:
- Type of signal
Analog CCTV signals are transmitted and received using video converters, whereas IP CCTV solutions require application of Ethernet media converters.
- Transmission distance
Transmission distance determines the type of optical fiber. Up to 100 meters, any type can be used - polymer or glass fiber (single-mode or multimode). At distances from 100 m to 2 km it is possible to use single-mode or multimode glass fibers. Distances longer than 2 km require to use single-mode glass fiber, due to the lower attenuation.
- Number of signals
The number of video signals (channels) in an analog CCTV system is the same as the number of cameras used. It determines the choice of a converting device with suitable number of inputs. If the system is also to convey audio, alarm, PTZ signals, the converter has to be equipped with suitable connectors.
In the case of IP CCTV systems all the signals (video, PTZ control, alarm, audio) are combined by a multi-input switch with an SFP module. Video monitoring of dispersed locations can be effectively implemented with the use of the optical cable with easy access.
In the case of IP CCTV systems all the signals (video, PTZ control, alarm, audio) are combined by a multi-input switch with an SFP module. Video monitoring of dispersed locations can be effectively implemented with the use of the optical cable with easy access.
Optical fiber transmission links for analog CCTV
Signals from analog CCTV security cameras can be converted into optical form by ULTIMODE video converters. Depending on the model, one optical fiber can carry signal(s) from 1, 4, 8 or 16 cameras. Thanks to the video converters and single-mode fibers, the camera points can be located at distances up to 20 km from the surveillance center. In many cases, the optical solutions are optimal also at much shorter distances, especially in places with high levels of electromagnetic interference or in locations exposed to lightning surges etc.
An analog CCTV system using fiber optic transmission medium
Depending on the number of cameras and the transmission distances, the suitable devices can be found in the tables below.
Single-mode ULTIMODE video converters
Multimode ULTIMODE video converters
Optical fiber transmission links for IP CCTV
Video streams from IP cameras are converted into optical form using Ethernet media converters or switches with SFP modules that can be selected according to the actual requirements. IP CCTV systems based on fiber optic transmission medium can be very extensive, with central or distributed management, as well as smaller ones, used in places with high levels of electromagnetic interference or in locations exposed to lightning surges etc.
IP video surveillance system in an office building, with a central point of management
The types of devices with different maximum throughput (limiting the number of connected IP cameras) and for various transmission distances are listed in the tables below:
Megabit ULTIMODE media converters
Gigabit ULTIMODE media converters
