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Hi!  

So I am attempting to connect my controller with my neighbors across the street and it is for sure 3000ft or longer.  I work in the datacom industry and know by the standards that you are not supposed to go over 100M without signal loss or degradation.  The LOR states you can go I think up to 5000ft which seems crazy to me but maybe its only using a simple protocol so it can go long distances?  Anyone with experience doing this?  Also most category cable only comes in 1000ft lengths so I would have to use inline couplers.  I was thinking of running fiber instead but don't want to incur the expense of the transceivers on each end - appreciate the help!!!

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Gotta get the datacom engineer side out of you on this one. This isn't TCP/IP. The RS485 standard runs at rates up to 10Mbit, and generally speaking can go at least 1200m (4,000 ft). 3000ft is 1000 yards, or 10 football fields (minus end zones.) That's a heck of a distance between you and the neighbor.  If you go the cat5 route, you might consider at least 1 or 2 of these in your long run. It will help make sure the signal is strong when you get to the other side. http://store.lightorama.com/rsnere.html

I've been out of the day to day cabling stuff for 10+ years, so I don't recall what type of loss you might encounter over fiber. Certainly overkill (imho) for what you are attempting.

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As Don said, as long as you are using LOR (or ELOR) network, 3,000 feet should not be a problem over Cat-5 cable.  If you are using E1.31 (DMX over Ethernet), yes, the 100M limit applies for Ethernet.  If that is the case, you would likely be better off with something like a Part 15 microwave link as opposed to almost a dozen switches en route to keep the Ethernet alive.

Over a half mile to the neighbor across the street?

 

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  • 2 weeks later...

Electrically, RS485 can go anywhere from ±1.5V to over 5V. Ethernet is ±1V. This voltage difference is one reason why RS485 can go farther.

Also, the bandwidth used by the RS485 LOR network is 57Kbps or 115Kbps, compared to 100Mbps Ethernet. The higher voltage and lower speed is what lets a LOR network be very long.

In order to control a large number of channels with a lower bandwidth, LOR puts intelligence in the controllers, which allows the network to give commands such as "fade down over the next 5 seconds", or "shimmer until the next command is received". Other protocols (such as DMX) must send the intensity for every channel about 40 times every second.

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