Whilst there is no doubt that network connectivity offers an increased range of benefits to security solutions, and especially those utilising video surveillance. Despite this, the fact remains that many sites with historical security implementations will be left with legacy infrastructure, commonly in the form of coax. Panasonic now offers a way to utilise this, leveraging the value of previous investments by repurposing the existing cabling with coaxial convertors.
A great number of security installers and system integrators are happy to have moved away from coaxial cabling and its many downsides. When it comes to cabling, coax is not one of the best to work with. It’s heavy and quickly fills conduit space, the cable is cumbersome and can be difficult to pull, it is susceptible to interference from a number of sources, the low bend radius means that at times the simplest routes cannot be utilised, etc.. Despite this, coax was an essential element when it came to CCTV installations in the past, and due to the popularity of surveillance systems, the reality is that many sites feature the legacy infrastructure in abundance.
Given that cabling is a significant part of any installation process, it does make sense to try and repurpose any existing infrastructure. Thankfully, coaxial cable is well disposed to carrying IP network traffic; indeed, the cable was used for network connectivity in the past. Because of this, it is not always necessary to implement a programme of ‘rip-and-replace’ with infrastructure.Instead the coax can be utilised to form IP-based network links.
To do this does require some type of conversion devices. These are widely available and there are a number of manufacturers offering Ethernet-over-Coax (EoC) solutions. When the cost of these is considered alongside the labour and materials investment in a ‘rip-and-replace’ scenario, they are very cost-effective. The benefits increase in longer reach applications, as often the transmission ranges of such products exceed the traditional 100 metre limitation of IP. Therefore there may be additional savings as extenders may not be required.
The latest offering comes via Panasonic, with its combination of the WJ-PC200 transmitter and WJ-PR201/4 receivers. The coaxial convertors can be used to repurpose coaxial cables as network links, and with PoE injectors can also allow power delivery to networked devices.
Specification
The coaxial convertors using two devices: a camera side device and a receiver. The camera side coaxial convertor is the WJ-PC200, which allows connection of a single device. The miniaturised device measures 76 x 76 x 36mm, and can be fitted into an existing camera housing. Where it is mounted outside of a housing, a simple coax cover is included. This allows the connection to be covered, thus preventing tampering to a degree.
The WJ-PC200 is powered from the receiver unit. The connections are for 10/100Base ethernet in and coax out. There is also a Link status LED.
At the receiver end, installers and integrators have a choice of either WJ-PR201 or WJ-PR204 units. These offer support for one or four channels respectively. Our test unit was the WJ-PR201. The units are suitable for rack mounting, and the ability to support up to 4 cameras per channel with the WJ-PR204 allows for 16 cameras per rack.
The WJ-PR201 has a single coaxial input and a 10/100Base ethernet output. There is also an input for 57V DC power in; a PSU is supplied. As with the WJ-PC200, there is a coax connection cover to prevent tampering.
The WJ-PR201 has three status indicators. These are for Power, LAN and Coax. The unit measures 104 x 44 x 98mm.
Panasonic’s figures are calculated with the assumed use of RG6/U coaxial cable. The WJ-PR201 and WJ-PC200 can be used over distances of up to 300 metres for PoE+ applications, up to 500 metres for PoE applications and up to 2km for non-PoE use. It should be noted that the PoE+ and PoE figures are for use with compatible Panasonic devices. With other third party cameras, the respective distances fall to 200 metres and 300 metres.
Transmission speed is quoted as 35Mbps (TCP) or 45Mbps (UDP) with the proviso that the transmission distance is less than the maximum figures quoted above. It is worth noting that with the WJ-PR204, the transmission speed is the total value of all four streams.
Installation
Installing the WJ-PC200 and the WJ-PR201 is very straightforward. The convertors are self configuring and require no adjustments or set up by installers or integrators. It really is a case of mounting the devices, making the various connections, and that’s it!
The devices are supplied with a manual, and most of the content addresses connections conditions such as the length of camera and receiver side ethernet cables, power budgets, etc.. All functionality is automated, and once up and running the devices are very much in the background.
Performance
On initial power-up, everything works as expected. That is only to be expected when you’re dealing with a solution that does not require any configurations. As long as the attached network elements are correctly configured, there isn’t really anything to get wrong.
As with any coax-based convertor, the only variable which might impact on performance is the quality of the coax! It must be remembered that analogue CCTV was pretty forgiving when it came to cable quality, and Benchmark has seen issues with both Ethernet over coax convertors and coax-based HD systems in the past when used on legacy cabling. This is especially pertinent if you’re working on a site where you don’t know the history of the infrastructure.
We tested the Panasonic convertors with a range of third party cameras, and all delivered what was expected from them. The convertors gave no reason for any concerns.
When compared to dedicated Ethernet links, the video streams transmitted across coax showed no obvious variance in image quality or colour fidelity. Any latency on the network link was similar over the coax, and certainly any lag or delay that certain products exhibited did not increase.
Motion remained smooth and there was no evidence of dropped frames, even when very fast activity was included in the viewed scene.
The video was tested using RG6 and RG59, and whilst the latter will impact on achievable distances, the streams are still of good quality as the maximum quoted distances are approached.
Verdict
Using legacy cabling makes a lot of sense, especially where existing infrastructure links various buildings across larger sites, or where coaxial cabling has already been run to perimeters or across large open areas. Reductions in time on site and the need for civil works makes the units very cost-effective too.
The WJ-PC200 and WJ-PR201 perform exactly as expected, and there was no difference between links using coax and the same devices using a dedicated Ethernet connection. As such, the coax convertors from Panasonic have to be recommended.
