Ethernet over coax (EoC) is not a new technology in the security sector. Many companies have been offering it as an option for a number of years, and the introduction of long reach systems, along with provision of power across legacy coaxial links, has raised interest in the technology. It remains something of a niche market, despite the benefits, typically because many installers and integrators prefer to deploy appropriate infrastructure where possible. Nitek offers another EoC to choice to installers and integrators with its Etherstretch Pro range.
It must be accepted that composite video was, in its own way, a spectacular success and delivered what many end users required in terms of protection. Admittedly analogue technology had its limitations, but over the years the constantly increasing popularity of CCTV saw it rise from being a security solution only viable to high risk sites with large budgets to one that almost every end user – regardless of their risk level or budget, was demanding.
One of the limitations of composite video was that every camera required a dedicated run of coaxial cable, and these all came back to a central location: either a control room or a bank of VCRs and later DVRs. This made the installation process slow and costly, with engineers often spending a significant proportion of their time pulling cable!
It did not help that coax is a pig to work with. The cables are thick and heavy (taking up much room in conduits), they have a low bend radius, are prone to interference and are slow to terminate. No longer working with coax is one thing that many integrators and installers enjoy when migrating to a fully digital platform.
The upshot of the popularity of composite CCTV is that many sites today which have previously used CCTV have a lot of legacy coaxial cable in situ. Few users will be willing to rip it all out unless they are going for a full infrastructure upgrade, so for many installers and integrators it represents a resource that can be repurposed.
Coaxial cable was used, many years ago, as a network connectivity medium, and it can still be deployed as such today. Because digital video signals require less frequency that analogue alternatives, the cable is more than capable of managing multiple data streams. The use of EoC converters allows existing coax to be repurposed as LAN links, and advances in the switches used have seen transmission distances raised above the 100 metres typical of LANs. The converters also increasingly allow the use of PoE as well.
While many EoC converters are aimed at the video surveillance market, the technology can be used for any network traffic. This includes other security technologies such as access control and alarms, telephony and other communications as well as standard business data traffic.
There is one issue, however, that must be considered. This is not a fault of EoC convertors or of the technology itself. However, it is a potential problem which is a hangover from the success of composite video
Analogue video was forgiving; very forgiving. It was possible to transmit acceptable quality video over low quality coax. Indeed, when the price of copper spiked some years ago, it was not unusual to see coax that did not have solid copper cores. Because of this, the quality of many legacy coax installations cannot be guaranteed unless the installation company was the one to originally install it and knows it to be high spec.
With many EoC systems, there is a reliance on high quality coax, and if that is not available then EoC will not be a viable option. This doesn’t mean that EoC is a non-starter; more that field trials will be required to ensure it can operate correctly over the proposed distances.
While there are a number of EoC providers well established in the security sector, Nitek’s Etherstretch Pro range offers another option.
Specification
The Etherstretch Pro range is made up of a number of convertors, including multi-channel and single channel devices. Our test system was made up of a ER8500C eight port switch, plus ET1500C and ET1543C single channel transmitters.
The ER8500C operates as an eight channel EoC receiver, network extender and PoE switch. It is capable of supporting gigabit ethernet, or 10/100 BaseTX if used with PoE to the edge devices, and gigabit ethernet to the network switch.
When deployed using RG59 coaxial cable, the ER8500C is specified as having a maximum range of 500 metres. PoE budgets (per channel) are up to 21.7W at 200 metres, 18.2W at 300 metres, 14.4W at 400 metres and 12.2W at 500 metres. The power supply for the PoE output is integral to the ER8500C device.
The unit has short circuit, over-current and over-voltage protection.
The multi-channel ER8500C has a short installation time as there is no need for configuration. Because Etherstretch Pro is transparent to the network, there are no IP or MAC addressing requirements for basic use with a single unit. If multiple units are deployed it is necessary to set an IP address for each ER8500C to avoid conflicts.
Status is shown via LED indicators on the front panel. These display network communication, link status and PoE power. There is an option to use the device’s integral browser-based GUI to check link and PoE status if required. Ports can also be named to simplify user interaction.
Connections for the ER8500C are simple. There are eight BNC inputs for the coaxial links, an RJ45 LAN connection and an SFP port. Aside from these, the only other connection is the power input (mains voltage).
The unit can be fitted to a standard 19 inch rack and takes up 1RU. A wall-mount version is also available, as is a 16 channel model.
The ET1500C is a single channel transmitter device which sits at the edge device end of the coaxial cable run. It is capable of supporting 10/100 BaseTX with PoE. It also has a maximum range of 500 metres.
The unit has protection against ground loops and power surges. Like the ER8500C, there is no need for configuration, and the EL1500C is transparent to the network.
Status LED indicators give a visual confirmation of network communication, link status and PoE power. Where the length of the run creates a drop in PoE levels, an optional 48V DC PSU can be used to increase power to the edge device.
Again, connections are simple with a BNC input for the coaxial link, an RJ45 LAN connection to the edge device and a power input for the optional PSU.
The EL1500C is also available pre-fitted into an IP66 rated enclosure, with a further variant including the enclosure and surge protection.
Finally, the ET1543C offers the same performance as the EL1500C, but has a different form factor.
Installation
As already mentioned, the installation of the Etherstretch Pro system is quick and simple. At the receiver end, the various coaxial links are connected to the ER8500C. The IP address of the receiver will need to configured via the GUI if you require advanced status information or are using multiple units. The ER8500C is then connected to a network switch which also has connections to any systems linking with the edge devices. At this point the receiver can be powered up.
At the edge device end of the coaxial run, the transmitter unit can be connected via its BNC. It will power up and the LEDs show that the device is communicating. It is then a simple task of connecting the edge device via the RJ45 port. At this point the power LEDs will display whether the additional PSU is required. The process is then pretty much complete.
If the GUI is used, it is fairly clean and intuitive. In truth, there’s not a lot in there that needs configuring. For the most part it will be setting the IP address and naming inputs.
One point to note is that the ER8500C GUI does not have a password set as default, and the unit does not have a secure password policy. Installers and integrators should ensure that the unit is secured with a strong password regardless or not of whether they intend to use the GUI or are implementing multiple units. This is not mentioned in the manual.
Performance
The Ethernet Pro system is very similar to many of the EoC options available in the market. When deployed with good quality well installed coaxial cable, it performs much as you might expect. As such, it lines up against the other market choices and the installer or integrator can pretty much pick the one they want.
Moving away from the ideal world into reality, performance will be impacted by lower quality or poorly installed coaxial cable. Again, this is not too different to many of the other EoC choices. We did note that when coax wasn’t ideal, the system inevitably required the optional PSU at the transmitter end if cable runs were over a few hundred metres.
Benchmark does have one coaxial set-up that runs analogue devices to an acceptable level but has been the nemesis of many EoC systems. As expected, video from the Etherstretch system showed ghosting and interference when this was used!
Verdict
The Etherstretch EoC system from Nitek does what it should do with the proviso that the coax infrastructure is in good condition and was installed using good quality cable. However, if there are coax issues, then its performance will suffer.
It does line up quite well with many other IP over coax solutions, and for many installers and integrators it’s a matter of paying your money and taking your choice. One thing that must be done is securing the remote network access!
As such, it achieves Recommended status in Benchmark testing.
