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Cat5 Wiring: # of pairs required.


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Anyone know the minimum number of cat5 wire pairs needed for Lor communication between boxes? If I run a single 4 pair wire out to each box in the yard can I use 2 pair for the connection in, and the other 2 pair for the connection to the next box?

All of our wiring is being buried permanently, I just want to make sure we have enough wire in the ground. All runs will be brought back into the hose so I can connect the units together in any sequence I'd like.

-Tom

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tom-lights wrote:

Anyone know the minimum number of cat5 wire pairs needed for Lor communication between boxes? If I run a single 4 pair wire out to each box in the yard can I use 2 pair for the connection in, and the other 2 pair for the connection to the next box?

All of our wiring is being buried permanently, I just want to make sure we have enough wire in the ground. All runs will be brought back into the hose so I can connect the units together in any sequence I'd like.


Four wires are used -- two for communications and two for accessory power. Not sure which is which off the top of my head. So theoretically, you could do what you want with 4 pair.

Not sure you really need to "home run" everything back to the house, although that would certainly give you ultimate flexibility. Physical order of the units doesn't matter in the LOR world...

-Tim
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tom-lights wrote:

Anyone know the minimum number of cat5 wire pairs needed for Lor communication between boxes? If I run a single 4 pair wire out to each box in the yard can I use 2 pair for the connection in, and the other 2 pair for the connection to the next box?

All of our wiring is being buried permanently, I just want to make sure we have enough wire in the ground. All runs will be brought back into the hose so I can connect the units together in any sequence I'd like.

-Tom

Due to the RS-485 Half duplex connection, you really only need 1 pair of wires, but a second pair is used so that everthing is connected to a common ground. I have not tested using only a single pair but in theory data transfer can still occur using a single pair.
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tfischer wrote:

two for accessory power.

I did notice the the 5 volts was sent out but I also noticed it doesn't seem to be used on the input side of the 16Ds I was wondering what it is used for. Do you know

Robogeek
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Excellent, thanks Tim and Robogeek just the info I was looking for.

Honestly, I'm home running everything in case I want to use the Cat5 connections for other things in the future during the LOR "offseason".

Looking forward to my first year of LOR. My fiance thinks I'm crazy. ;) But I'm sure that's not an uncommon phenomenon here.

-Tom

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robogeek wrote:

tfischer wrote:
two for accessory power.

I did notice the the 5 volts was sent out but I also noticed it doesn't seem to be used on the input side of the 16Ds I was wondering what it is used for. Do you know


Yes, it powers things such as the "serial dongle" (the RS232 9-pin to RS485/RJ14 connector), and I believe also the Easy Light Linkers and possibly the MP3 player (not sure about that one).

-Tim
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tom-lights wrote:

Anyone know the minimum number of cat5 wire pairs needed for Lor communication between boxes? If I run a single 4 pair wire out to each box in the yard can I use 2 pair for the connection in, and the other 2 pair for the connection to the next box?

All of our wiring is being buried permanently, I just want to make sure we have enough wire in the ground. All runs will be brought back into the hose so I can connect the units together in any sequence I'd like.

-Tom


A quick note. I'm running Cat5 in my christmas light strings. I will be using these for control LOR 1 to LOR 2 and a wireless alarm connected in to my house system on a 24 hr loop. If my wires are cut, it will trigger my alarm system. I only need two wires for the closed loop with a resistor in the end, I will be using the brown set.



Tim
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You may want to find a way to test this out. You can do the same thing with CAT5 and Ethernet or 4-wire digital phones, but the effective maximum distance for the signal wire drops considerably due to crosstalk (the longer the wire, the more the signal from the one pair's data becomes noisy interference with the other pair's signal).

I don't know what the data rate for RS-485 is, but IIRC it's considerably lower speed than ethernet, giving more leeway for error handling.

Moving Target in NC

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Regardless of the type wire, Cat-5, Telephone, make sure it is designed to be buried due to corrosion, moisture.

Outiside wire will most likely be gel-packed.

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