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Old 12-17-2018, 10:51 AM   #1
Spork Schivago
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Default Active Optical Cables

I have a situation where some long cables would come in handy (ie, DisplayPort, USB, maybe even RJ45 / USB). Because of length restrictions with these cables, I believe one of the ways to go would be using an AOC cable.

I'm curious as to how hard they are to make. My limited understanding is various connectors on one end, fibre in the middle, and something to convert the electrical signals to light and back again...for the RJ45 / USB cable, what I mean is RJ45 on one end, USB on the other.

Has anyone ever successfully made an Active Optical Cable (AOC)?
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Old 12-18-2018, 12:19 PM   #2
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Default Re: Active Optical Cables

Can the problem be solved in some other way than using fiber optic cable, especially since you have to do a protocol translation anyway?

For these high speed applications, the wire transceivers are already pushed to the limits and needing an optical transceivers that exceed that of wire, at least if you want to multiplex multiple wires to one fiber which may be necessary to deal with timing issues. Ideally the optical link is incorporated into the protocol to ensure integrity of all data that needs to be passed through.
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Old 12-18-2018, 12:38 PM   #3
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Default Re: Active Optical Cables

Quote:
Originally Posted by eccerr0r View Post
Can the problem be solved in some other way than using fiber optic cable, especially since you have to do a protocol translation anyway?

For these high speed applications, the wire transceivers are already pushed to the limits and needing an optical transceivers that exceed that of wire, at least if you want to multiplex multiple wires to one fiber which may be necessary to deal with timing issues. Ideally the optical link is incorporated into the protocol to ensure integrity of all data that needs to be passed through.
Eccerr0r,

I've tried thinking of other ways and I think the AOCs will be the most cost effective solution. I am down for other ideas though. One thing for certain is I need to run certain cables further than their limits (if they're Direct Attached Cables (DAC)). For example, DisplayPort cables are specified and tested to run 5 meters without the need for a booster station. You can run them a little further I guess, but they're specified for 5 meters. USB cables are specified for 5 meters (16 feet, 5 inches) for USB 2.0, and 3 meters (9 feet, 10 inches) for USB 3.0. I will definitely be running the DisplayPort and USB cables longer than that. I will be using USB 3.0 cables...

These cables will be permanent links. I will run them through joists and through conduit to wall plates which will be their final destination. So I can plug into the wall plate and have access to what I need. I cannot think of any feasible alternatives to the AOCs.

Last edited by Spork Schivago; 12-18-2018 at 12:40 PM.. Reason: Made a mistake on the specifications for DisplayPort cable lengths
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Old 12-18-2018, 12:42 PM   #4
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Default Re: Active Optical Cables

DisplayPort's max might actually be 3 meters. I'm going to be using 4k resolution, and I think that might affect how long I can run a Direct Attach Cable. I might be able to go further, but I might not have that 4k resolution. So I think that AOCs are the way to go here...I'm running them from a rack to a workbench, where I have a few workstations and one of those expensive CAD type monitors.

Maybe I should look into purchasing premade ones. Cables2Go makes some nice cables I guess.

Last edited by Spork Schivago; 12-18-2018 at 12:43 PM..
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Old 12-18-2018, 04:35 PM   #5
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Default Re: Active Optical Cables

Quote:
Originally Posted by Spork Schivago View Post
I have a situation where some long cables would come in handy (ie, DisplayPort, USB, maybe even RJ45 / USB). Because of length restrictions with these cables, I believe one of the ways to go would be using an AOC cable.
Don't know what device sits at the far end, but you might consider access / sharing thru WiFi (ac band) with a good coverage will deliver all the bandwidth you need. There are plenty software tools to remote / sharing access and even more dedicated and performance tuned ones for specific ports e.g. USB.
Thereby you will avoid passing cables, dealing with optical transceivers and protocols, etc.
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Old 12-21-2018, 05:40 PM   #6
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Default Re: Active Optical Cables

For USB, that might be an option I didn't think of. For the DisplayPort cables, I don't think that's feasible, because of how much data is based through. Internet says 4k (3840 x 2160) @ 60Hz with a 16 bit colour depth and a chroma sampling (gotta research chroma!) of 4:4:4 requires 35.64 Gbps. (https://www.extron.com/product/videotools.aspx ). There's the link to the tool I used to calculate that. I don't think we can transmit wirelessly that fast yet. If we could though, I'd imagine that'd be pretty expensive as well.

One thing I was looking into (my research didn't go too far) was these IP based switches. They're KVM type switches but IP based. My understanding is I'd use special cables to plug into my devices (like DisplayPort). Then I could connect via TCP/IP to the switch and access the devices. The only thing that discouraged me from going this route (as it seemed like what I was looking for) was I couldn't find an IP based switch that could handle the 4k data. I spent (to us) a lot of money on a professional 4k monitor and an nVidia Quadro P4000 video card. I really want that 4k! From what I've read, the IP based switch would be the perfect solution, if they supported that resolution, but I don't think they were designed so much for transporting 4k video through ethernet.

Maybe I should look at the USB cables and the video cables as separate problems...these are the devices I'm connecting to and the cables they use:

two PDUs: RS-485 (looks like an RJ45 jack) or I can connect via USB
Cisco Router Console (serial or Micro-USB)
three Cisco Wireless APs (RJ45 serial on the AP end, USB or serial on the workstation ends)
two to four DisplayPorts that transport the 4k @ 60Hz to wallplates.
two USB ports that go from the server (for keyboard, mouse, thumb drive, etc) to a wallplate

The idea was to have one or more custom made wall plate(s) with the various connections. They'd be permanent link, and then I would plug in the various cables from the workstation (or whatever device I'm using to gain access) directly into the wallplates. I hope that was clear enough.
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Old 12-21-2018, 05:54 PM   #7
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Default Re: Active Optical Cables

There's a couple more things. For the PDUs, I don't think I'll even run the serial cables, because the CLI is very limited, but the web interface has a lot (which, from my experience, is usually the other way around).

There's an HPE switch I need access to as well, but that's through a special network port. Mainly, the display (and I forgot, one VGA port) plus console access to the Cisco stuff and the USB stuff to access the server.v I'd imagine once I get the wireless APs configured, I wouldn't need to access them very often, if at all. It'd still be nice to have a permanent cable installed so if I ever needed to, I could easily access it without having to physically take the APs done and hook a cable to them.
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Old 12-22-2018, 11:42 AM   #8
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Default Re: Active Optical Cables

Since UHD (4K) is a must, for the length you require AFAIK you have only 2 options:
1. Shielded CATx cable
2. Fiber optic
Both options come from shelf: transmitters, receivers, extenders, switchers, ...hassle free!
But the overall price may likely cost you more, per access point (wallplate), than 3 to 4 times a nVidia Quadro P4000 video card price
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Old 12-24-2018, 06:57 PM   #9
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Default Re: Active Optical Cables

I think at this point, I'm going to have to make some decisions. After Christmas, I will sit down and create a spreadsheet and write down every device that accepts a console cable, the type of cable it uses, the maximum length a DAC version of that cable can be ran, whether I need AOC or not, etc.

I know for certain I need two DisplayPort cables and two USB cables to go along. The rest I could survive without, but it wouldn't be the way I'd want it. I mean I could do it if I had to. For example, the wireless APs, I could take them down and use a short cable next to a workstation to program them. They're powered by PoE and I do not have many PoE ports. I have no injectors, so that'd be an issue I'd need to work out.

That spreadsheet should give me a better look at the overall picture. The one concern I have with these permanent link cables is IF someone where to gain access to the access ports, then that's one security wall breached. We'll keep the SOC / NOC / DC secured, but I dunno. If you open the rack, alarm goes off and we're notified via cell phone message. If you plug into one of the access ports, we'd never know. The devices will all be password protected, but I dunno, it feels like maybe from a security standpoint, it might not be the best route to go? I dunno.....I could also run the cables and just not plug them into the devices (except maybe the wireless APs) unless needed? It wouldn't be hard to open the rack and just plug the cable in when I needed it...I dunno.

The custom built wallplates is going to cost a bit of money as well. I'm just really hoping it's not going to be like the direct fibre line event. Call various companies and the price was a bit of a shock! 25k a mile for the one company, 50k total for the other company. Both where just very rough estimates.

Or the PoE 48-port CAT6A switch. Price for that was a bit of a shock! I knew it'd be high, but wasn't expecting it to be that high!
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Old 12-24-2018, 07:01 PM   #10
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Default Re: Active Optical Cables

We have shielded CAT6+ cable, really good cable. Well, it's actually F/UTP (foiled / unshielded twisted pair). The F foils all the cables, and there's a drain wire. To me, I don't think there's much difference between the two in our environment. I think F/UTP is easier to work with and with STP, we would really see any difference at all.

But I'm not following how the shielded cable would be used. For DisplayPort, it's not capable of providing the required bandwidth, correct? Let's look at one of those RJ45 / Serial cables. Using shielded cabling wouldn't allow me to necessarily use longer cables...the hardware is still the one setting the signal strength...if I boosted it, then yeah, I could see where that'd make a difference....am I misunderstanding the CATx cable suggestion?
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Old 12-27-2018, 02:10 PM   #11
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Default Re: Active Optical Cables

Fiber optic is cheaper than any cable you can think of…!
Therefore the huge price comes from really expensive transmitters, switches and receivers capable to share the display port at UHD resolution.
To me they look unaffordable and quite unnecessary but don’t really know what you’re trying to accomplish… the overall picture.
Sorry but imo it seems as if you’re trying to share the mount Everest… I think should think on building mountains where they’re needed instead.

Plus, security concerns must be a primary concern and of most importance.
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Old 12-28-2018, 05:20 PM   #12
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Default Re: Active Optical Cables

I need to be able to view what's coming from a video card x amount of feet away, and I need to be able to access certain devices x amount of feet away. Some (not all) of those devices are way past the limitations of the DAC version of the cable specs. These are going to be permanent link cables (they don't get unplugged).

I'm talking to Cables2Go and they think we might not have to go Active Optical for the majority of them, if any. I have to give them over-all lengths and pinouts for the speciality cables (ie, the console cables). The Active Optical Cables convert the electrical signals to light pulse, send it through fibre, and then back again. Like you mention, the price isn't because of the fibre, but the converting the electrical signals to light pulses and back again. Those transceivers that are built into the cables are a bit pricey I think.
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Old 12-28-2018, 05:40 PM   #13
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Default Re: Active Optical Cables

I'll try to explain it a little differently. I have a DC that has a rack. The rack has doors that must remain closed most of the time. I cannot open the doors and have various cables permanently coming out of the doors. I want to hook various cables to various devices in the rack (usb cables for keyboard / mouse / flashdrive / whatever, displayport cables for video, etc) and run them through the access port on top of the rack, through floor joists, etc, to a wallplate or two.

I have wireless APs installed in ceilings on various floors. I want to install permanent link cables that run from the wireless APs through the ceilings / walls to a wallplate.

The wall plates will be installed by one of my workstations. Instead of plugging my monitors directly into the video card installed in the server in the rack, I want to be able to plug the video card directly into the wallplate. Instead of plugging a keyboard / mouse / whatever into the server, I want to be able to plug it directly into the wallplate. Instead of having a console cable hanging from the ceilings, I want to be able to just plug a USB port into a wallplate and access the APs console.

There's physical limitations on how far certain cables can be ran and generally, I believe you use something like an IP based KVM (such as this one: https://www.hpe.com/us/en/product-ca...s.7738586.html )

However, because I have the need for the 4k display, that IP based KVM wouldn't work for the display portion. I could purchase the KVM and then just deal with the DisplayPort issue, but I was hoping to not have to purchase the KVM at all. I was thinking it'd be a little overkill for my needs at this point.

I hope that clears things up a bit.
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Old 12-30-2018, 10:57 PM   #14
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Default Re: Active Optical Cables

Quote:
Originally Posted by Spork Schivago View Post
I could purchase the KVM and then just deal with the DisplayPort issue, but I was hoping to not have to purchase the KVM at all. I was thinking it'd be a little overkill for my needs at this point.
I hope that clears things up a bit.
Got the overall picture.
The main problem (cost wise speaking) is with 4K UHD if you need longer distance than the standard to avoid the common called ‘digital cliff’.
You’ve got 2 choices: over cat6 cable or fiber optic.
Over cat6 might be more cost effective, since the equipment is cheaper, but the overall bandwidth ~10Gbps is barely enough to handle the 4K resolution @60fps.
In fact it isn’t enough: visually lossless compression (HDR10) is used do deliver 4K @60fps 4:4:4. This implementation might suite a home theater scenario but fails when USB, Ethernet and other need to be distributed as well.
Therefore, to meet your needs for longer distances, you’re bound to use fiber optic.

Thus leaving DisplayPort issue for later wouldn't be wise, while being a little overkill does
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Old 01-06-2019, 09:20 PM   #15
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Default Re: Active Optical Cables

@Spork Schivago
Got back from New Year's celebration... just a nice excuse to take some time for me.
Nevertheless your problem got stuck in my head… found myself Thinking Outside the Box!
Guess what?
I’ve come up with a very reliable and cost effective solution.
If you didn’t move any wheels yet and have interest in this solution, just let me know.
[afterwards give me some time to catch up my work while putting it all into words]
.
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