Upcoming Ethernet Over Coax Test -- What Do You Want Us To Test?

In the next week, we'll be starting a test of a few different EoC adapters. Right now the list includes:

  • Veracity HIGHWIRE PowerStar, since it's the top tier model from Veracity, one of the big names in EoC (or at least as big a name as you can be in the market).
  • Altronix eBridge, since it's lower cost and we've heard a number of integrators start using it.
  • EnConn Mini Power, which is lower cost than even the eBridge.

For testing, it seems the key factors to take into account are:

  • Ease of use: is it simply plug and play? Are connections made reliably? What usability issues are there?
  • Are there noticeable increases in latency and packet loss?
  • How does throughput match up to typical UTP Ethernet links?
  • How do all of the above vary at different lengths of cable?

Is there anything else we should be looking for?


It would be great to test in a real environment or at least to simulate one. One big advantage of the technology is probably to re-use existing installations. By experience we all know that the cabling of coax is far from being perfect on site (grounding for example). While analog cameras, transmissions and encoders were able to 'tolerate' a lot of these issues I would doubt it will be the same for EoC.

So 'playing' with the cables and the connectors, use of extension connectors or 'T' connectors would be a great input although I understand it will be difficult to quantify this from a test perspective.

thx

We've been discussing this internally and we would like to test in a real environment, but our office doesn't have any existing installed coax, nor do we have any pieces of old coax. We could use another site, but that introduces coordination problems and other issues of access.

So instead, we had an idea. If any member could send us a piece of old coax, we'd be willing to pay for it. If it's a piece that's been removed from an actual install, that would be especially great. If it's from a spool you've had kicking around the back of the warehouse for ten years, also great. We have full spools of cable here, but getting old cable is a different story.

Ethan, I should have a couple coils of lighty-used (ie. in-home) RG-59 kicking around. Not terribly long, probably <100'. I also have several lengths (probably 30'-50' each) of RG-59 siamese that was removed from a site during an upgrade. Yours if you want them.

I recently came across this product from Phybridge that has says it's a 24-port managed ethernet over coax switch. http://www.phybridge.com/products-services/coax/cleer/

Vigitron MaxiiCopper.

+1 for Altronix.

Also this is Chinese brand that I would love to know more about:

http://www.utepo.net/product_details.asp?id=409

I think any test of EOC devices should include Network Video Technologies new NV-EC1800 series. Not only does it work over Coax but UTP, STP and 18ga/2conductor wire.

C, you should disclose that you are an NVT rep.

I don't have a problem with your comment as it provides some details to support it but it's important that relevant affiliations be disclosed up front.

John, point taken.

Is the EC1800 shipping? I can't find any reference to it on the NVT site or even Google.

One of my customers has standardized on NVT. It can use one transceiver at the head end and four in the field. Coax / TP - same product, just different adapters. We've had good luck with it and all of the configurations. I'd like to see it against other products.

http://www.nvt.com/content.php?type=template&key=productfamily&ckey=eoc

http://www.nvt.com/content.php?type=template&key=productfamily&ckey=eo2

Chuck, based on your and other comments, we're going to add NVT to the test. Just ordering up parts now. Thanks!

Hi Ethan, I would find it useful to know how much power the EoC converters use based on your measurements rather than nominal specs. One of the seemingly attractive reasons for using EoC must be to save costs on replacing old coax with Ethernet cable. However once the cost of EoC converters and their ongoing power consumption is taken into account, I wonder if the cost of recabling might look more attractive as well as eliminate potential technicalities introduced by EoC converters?

I would also like to know how well these EoC converters work with different grades of coax cables. When working with SDI video, I found that floppy SDI cables were OK for standard defintion video but not for the higher data rates of high definition and beyond. HD-SDI required better quality cables which felt much stiffer due to the wider copper core. I'm guessing EoC converters might have similar dependancies to work reliably.

Thank you in advance for what is already looking like a very interesting and useful test.

Luke,

HD-SDI is a lot more critical of cable type and construction that EoC. HD-SDI transfers data at up to 3Gbps whereas EoC uses the same bitrate over coax as Ethernet does over UTP.

Although most EoC products specify 75 ohm cable, in actuality, they are not that critical of cable impedance. Vigitron sells an adapter for their EoC products that can put data and power on a single pair of UTP. Their Vi0030 adapter looks like a miniature balun but in actuality it is just a BNC-to-UTP adapter so in effect, the Vi24xx EoC adapters are seeing balanced 100 ohm cable connected to their unbalanced 75 ohm connectors.

We tested the Vi2401A products on a single pair of CAT5e through two 66 blocks and obtained good results with an Axis P3364 at over 700 feet. The total power draw of the Axis camera plus the Vi2401A's required Class 3 PoE but it worked flawlessly. We were amazed that we could provide power and transport video data that far over a single pair of 24 gauge UTP.

Hi Carl, thanks very much for sharing your experience with these products. That's very helpful of you. These days there is even 12G-SDI but I appreciate that IP video should be far less demanding than even 1.5Gbps HD-SDI.

Veracity Longspan, Comnet Copperline and Nitek Etherstretch products. I'd like to see UTP tests too. For instance NVT1701 supports both with an adapter for UTP. Would also like to see that some testing is conducted with PTZ cameras as well as fixed. We ran into a specific issue with Panasonic PTZ cameras when using NVT and Veracity Longspan that seemed related to latency but didn't have that problem with the Copperline product. That being said, we also tested Axis, Avigilon and Bosch PTZs and they all worked fine with all three products so it's something peculiar with the Panasonics.

As far as testing UTP: we'll consider it for a future test. We're going to keep this test coax alone, simply because it's the more common use case.

What I'd like to see:

Overall throughput testing using a tool like iperf to see if there is any difference in the max theoretical throughput of the various units.

The above test, done with both large and small MTU's, many of these devices look to be more than just passive converters, are they prone to issues from lots of small packets for example?

For units with head-end multi-port aggregators, tests similar to the above with more than just 1 or 2 end-points.

What I'm curious about:

Are these units reliable for a basic 1 or 2 cam connection (I think so)

Are these units reliable as a "trunk" line, lots of traffic, high continuous througput (probably, not sure)

Are there scenarios where they become less "transparent" and can cause increased collisions, packet loss, etc. (not sure, I suspect yes in extreme cases).

We have dozens of analog cameras that have coax on both the camera and head end side, with fiber in the middle. We’ve discussed how EoC would fair in this type of scenario? Also, how many EoC adapters support differing control protocols, namely Pelco C.

Tony,

Why would control protocol matter? Data is data. If you can transport control over a UTP network, you should be able to transport it over an EoC network.

Tony,

As an NVT rep I am checking on the coax-fiber-coax scenario. I don't think there is an issue since we are dealing with Ethernet traffic. The design may differ depending on whether you are aggregating those cameras into an IDF after the first coax leg before converting to fiber or having to handle each camera individually to the head-end. Just a matter of what models for the application. Of course power would have to be available at each demarc point. The second part of your question about PTZ protocols would not really be relevant as you are no longer dealing with Analog video. With the EOC concept, you have already replaced the Analog cameras with IP. We are not dealing with Encoders here. Your control signals to the cameras would be Ethernet and not Pelco P, D or RS485.

Hope this helps.

In the spirit of full disclosure, I failed to identify myself earlier as Undisclosed "C", NVT rep. Sorry...

NVT T-Bus, particularly the higher end managed models.

Ethan,

I am Director of a small CCTV company based in China, and we have such device which is designed for CCTV using the Powerplug technology but has been specifically taylored for easy use.

Information relating to this is on www.eocbox.com

Just tossing in a couple thoughts here:

1. The cost of additional power for EoCs was mentioned... looking at the specs for a basic Altronix eBridge 1CRT, they state "12VDC/275mA, 24VDC/110mA, 16VAC/375mA, 24VAC/200mA." - in other words, around 3W. About the same as your average IP camera. Probably not enough to be a major cost factor.

2. I've used PoE eBridges over baluns before, quite by accident: installed them on both ends of a coax run, only to discover later that at one point the run went through station-Z (22/4, untwisted) using baluns. The camera was working flawlessly alongside two others that were using coax the entire length; in fact, the only reason I found out it went through baluns was in the process of tracing another run that was non-functional. Turned out THAT run had been disconnected at one of the baluns, and in fact, both coax feeds were passing through the same 22/4 wire. Those two cameras have been working problem-free for several months now.

What ever happened with this? Will you be including the Phybridge CLEER switch? I would like to see it included if possible.

Careful - if we disclose too much competitive info, someone could claim the $10,000 prize from Phybridge - http://www.phybridge.com/training/phybridge-challenge.html

Ethan, John...You should take the Phybridge challenge.. it's open to everyone..

Dick, no offense but that 'challenge' clearly bumps the IndigoVision Sweepstakes out of the top spot in our list of 'Most Insulting Contests Ever'.

We are confident in our claim that we created the EoC challenge. If you can find a better enterprise-grade switch with more enterprise-grade features, you can win $10,000.

Not will win? Where did their confidence go? How many can win? No terms or conditions?

If that's not bad enough, there is the shameless sexist appeal to the eager, if underfunded party girl. Note she is 'fronting' the only hundred dollar bill, not exactly inspiring.

Finally, even if no one objects to the lack of rules, cash and candor, this contest cannot turn out well.

Since if no one wins everyone will think it a scam, yet on the other hand does anyone really think that Phybridge is going to announce that Swanky Switch makes a product better and cheaper than theirs? And pay the $10,000 at the same time, (to an employee of Swanky Switch, no doubt)?

Keep us posted...

What does that even mean? Are we supposed to get into a debate with a manufacturer about "a better enterprise-grade switch with more enterprise-grade features" so we "can win $10,000."

We bought 4 or 5 manufacturer's EoC adapters and it is in queue to test.

Phybridge purchased NVT and the T-bus product is likely to be replaced with the Phybridge CLEER product.

Connector types - crimp v compression and as this is firmly in the realm of retrofit -compatibility with multi cable types - RG-59, Rg-6, Rg-11?

And thanks again.