Distribution has a lot of meanings in Digital Signage. It can mean anything from getting the same message to all of a companies stores across the country to getting multiple various messages across a college campus. We have tackled both scenarios and many variations in between with the Retriever, and I’m going to dive into a few of them to illustrate what’s possible. I’m going to point out specific manufacturers and their products that we’ve used. I do this not to eliminate other possibilities, but to give you the benefit of our research and experience with some great companies with awesome products. While I’ve used these technologies with the Retriever, most should work very similarly with other display technologies as well.
I’m going to simplify matters by categorizing ‘distribution’ into internal and external varieties. It is important to note that these can be intermixed as well. I’ll define internal as generally content emanating from one content source (media player/content server/Retriever) to one or multiple screens; while external involves getting your content to various locations that are not directly wired together. These locations may be across the street or across the country from each other.
External distribution is completely dependent on your chosen signage solution and how that solution distributes it’s content. The Retriever can handle identical, separate, or some combination of the two for distribution to multiple monitors, buildings, states, etcetera. Whatever signage system you chose should be able to take advantage of your content, reuse and modify it, and distribute it across multiple sources easily.
Now that we briefly covered external distribution, let’s get into the nuts and bolts of internal distribution.
1 to 1 – Or just plug it in.
You’ve got an output from your source and you’ve got an input to your display. Hook it up already! Just plug that cable in and revel in your techno-wizardry as your display magnificently lights up. Couldn’t be simpler, really.
1 to (sorta) 1
You may run into one or both of the following issues. Your output and input are different signal types, or your output is X distance from your input and your signal type doesn’t support that length (at least to spec!).
Dealing with varying signal & connector Types
If you’re output signal doesn’t have a corresponding input on your display you’re most likely still in luck. Depending on the exact situation you may just need the correct cable, an applicable adapter, or a cruddy converter.
Many digital formats can intermix without any sort of conversion (and generally the less conversion the better!). HDMI, DVI-D, and M1-DA (and usually DVI-I, DisplayPort, Mini-DisplayPort, Mini-DVI, and Micro-DVI) all connect together without conversion, you just need the right cable. You could also use an adapter in this type of situation, but then your introducing another point of failure (accidental disconnection and/or equipment failure). You also introduce more signal loss the more connectors you’re heading through, and the more signal you lose in connectors, the harder it’ll be to reach your desired length as you approach the spec’s limits.
Now, adapters certainly still have their place. Adapters are wonderful for getting from your output to your input without conversion, when a fully native cable doesn’t exist. For example, the Mini-DisplayPort on a Mac Mini can natively go to a VGA display in addition to it’s digital capabilities. Note that there are Mini-DisplayPort to VGA native cables, but we’ve had issues with resolution detecting/setting on Apple devices when not utilizing the Apple branded adapter. So the applicable VGA adapter from Apple is the suggested route here.
As for cruddy converters. Allright, that’s really not a fair statement. Sometimes, albeit rarely, conversion is the right, logical step. Most of the time, however we would recommend melding display technologies that were made to work together. Why? Due to the fact that most of the time you have to convert a display technology from one format to another you’re going to lose some quality, increase your costs, and again introduce another point of failure, not the best place to start. Now that said, converters do have their place. Perhaps a school building with 100 analog tv sets. You’re not going to get any form of digital signal into those. Converters (and in this case modulator(s) and splitters/taps) are the best answer, short of replacing all of the displays of course!
Also related to converters, but in a slightly different category are baluns. Baluns are like converters in that they change the connector type, but they don’t don’t change the signal type (at least not in the end). Baluns use an intermediary signal & connector between your output and input, and I’ll delve into more detail shortly.
One of our recommended manufacturer’s, Monoprice, has a great compatibility matrix on their site. I’d check them out and get some great, easy to use cables, adapters, and/or converters.
Extending the spec and/or using the cable that’s already in the wall
There are lots of specifications out there for what cable can go what distance with certain signal types. I’m going to focus on what we recommend for 1920 x 1080 video. HDMI cables we limit to 50′, DVI cables we limit to 15′, and VGA cables we limit to 150′. HDMI and DVI cables carry digital signals, so they’re pretty much all there or not there at all based on whether the cable has delivered the signal properly. The only time I’ve seen a digital picture degraded was when I sawn “sparkles” on a set we ran an HDMI cable 75′ from the source. In actuality, it was not a “snowy” picture, but actually pixels that just were all white due to a lack of data for a given pixel on a cable run longer than is recommended. VGA, on the other hand, carries analog signals, so it’s distance and cable quality can have a more dramatic effect on the actual visual quality of the picture.
Then there’s the concept of baluns. Baluns can help you overcome the spec/rule of thumbs above by using a sending and receiving balun. These little marvels can also help when you need to get a signal from point a to point b utilizing existing cabling. Various baluns exist and are highly reliant on the manufacturer for recommended distance and resolutions they can handle. One manufacturer, we’ve had great success with is Intelix. We’ve used various baluns and distribution systems from them with great success. Unlike some other spec sheets that we’ve run across, we’ve yet to uncover one of theirs that has over promised and under delivered.
One other caveat of baluns that the use of unshielded cable can give unpredictable results. While most video cable has shielding around it to help prevent unwanted interference, most cat 5 or 6 cable does not have this type of luxury. You may often get away with it, but putting in shielded cat 5 or 6 will give you a much higher piece of mind. We once put in unshielded cat 5 on a distribution job and it passed fairly close to the elevator for the building. Every time the elevator headed up or down, the video lost signal due to interference. Shielded cat 5 took care of the issue right away.
1 to 4 or less
There are many types of splitters out there. They biggest key is to always get an active splitter. None of the video signals we’ve talked about here were designed to just take a “Y” or “Splitter” and go from 1 source to 2 or more displays. You need an active splitter that plugs into a wall to process and actively split the signal. We’ve used monoprice.com again for HDMI and VGA that work well and are very cost effective. Despite the active split, you still need to keep the rule of thumb for your cable type in mind when determining placement and distances. You can also use a system designed to use a balun-type splitter to instantaneously go from your given signal type to 2, 4, or more cat 5/6 outputs. Then you need to buy the appropriate number of receivers for the other end.
1 to almost any number higher than 4
I’ve been saving the best for last. What if you have 100 displays, it certainly would be complicated to try to split HDMI or baluns up across 100 displays, not mention extremely costly! Enter the ZV line of products. They make several amazing little machines that turns a 1920 x 1080 VGA or component signal into a digital cable channel. This has several repercussions including utilizing cheap (and maybe even existing) coaxial cable, combining multiple content streams onto a single cable, granting incredibly long distance runs, and splitting as many times as you want for very little cost.
You may already have coax in your walls, it is after all what video’s been run on for years. Composite video, Component video, the Cable companies, and the satellite companies all utilize coax cable. It also is a very cheap cable that has shielding inherent in it’s design unlike cat 5 or 6.
Another benefit is that you can easily cram 135 content streams or more onto a single cable. This gives you plenty of channels to use for your own content, or the ability to put your content down the same lines you’re using for cable or satellite. This grants incredible flexibility and cost-effective distribution.
The distance you can go with coax is also incredible. Our record is currently 1500 ft including a few splitters along the way. You may need to jump between the coax size families along the way, but still very limitless on that front.
One last benefit I’ll point out for the ZV systems is how you can split the signal so cheaply. This works on 2 fronts. Once it is a digital cable channel, you can utilize the HDTV receiver that has been required in all TV’s manufactured since March 1, of 2007. Since you utilize the built-in tuner, you have no per display fee for receiving your signal. This leaves you free to grow to as many displays as you want without any additional points of failure or equipment to buy. You may need to be careful you haven’t bought a monitor as they don’t have the same requirements tuner-wise as a tv. The other reason this splitting is so cheap is that every time you need another tap you can utilize another cheap coaxial splitter to get the signal split out. We’ve gone to over 300 tv’s with 8 content streams utilizing boxes from ZV.
Wrapping it up
We’ve covered a lot of ground on distribution, and there’s a lot more nitty gritty to it. Everything from distance to splitting helps to narrow your choices of the best options out there. If you’ve got questions feel free to give us a shout and we’ll do our best to help you navigate through the available solutions to find the highest quality, most reliable, and cost -effective solution out there.